diff --git a/.npmignore b/.npmignore
index 65b188954..fee6e22df 100644
--- a/.npmignore
+++ b/.npmignore
@@ -16,3 +16,4 @@
 !sdk.js
 !sdk.d.ts
 !.jsonschema.json
+!jsconfig.json
diff --git a/.xo-config.json b/.xo-config.json
index e30f926f3..49d31dd8a 100644
--- a/.xo-config.json
+++ b/.xo-config.json
@@ -2,6 +2,7 @@
   "prettier": true,
   "space": 2,
   "plugins": ["import"],
+  "extends": ["plugin:jsdoc/recommended"],
   "rules": {
     "sort-imports": [
       "error",
@@ -27,7 +28,8 @@
         "newlines-between": "never"
       }
     ],
-    "no-console": ["error", {"allow": ["warn", "error"]}]
+    "no-console": ["error", {"allow": ["warn", "error"]}],
+    "jsdoc/require-file-overview": "error"
   },
   "overrides": [
     {
@@ -46,6 +48,12 @@
         "svgo.config.mjs"
       ],
       "nodeVersion": ">=18"
+    },
+    {
+      "files": ["svglint.config.mjs"],
+      "rules": {
+        "max-depth": "off"
+      }
     }
   ]
 }
diff --git a/jsconfig.json b/jsconfig.json
new file mode 100644
index 000000000..ce221ee02
--- /dev/null
+++ b/jsconfig.json
@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "target": "es2022",
+    "module": "node16",
+    "moduleResolution": "node16",
+    "checkJs": true,
+    "skipLibCheck": false,
+    "strict": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "forceConsistentCasingInFileNames": true
+  }
+}
diff --git a/package.json b/package.json
index 4ebcdeecf..1414bad2f 100644
--- a/package.json
+++ b/package.json
@@ -86,10 +86,12 @@
   "devDependencies": {
     "@inquirer/core": "8.1.0",
     "@inquirer/prompts": "5.0.2",
+    "@types/node": "20.14.2",
     "chalk": "5.3.0",
     "editorconfig-checker": "5.1.5",
     "esbuild": "0.20.2",
     "eslint-plugin-import": "2.29.1",
+    "eslint-plugin-jsdoc": "48.2.8",
     "fake-diff": "1.0.0",
     "fast-fuzzy": "1.12.0",
     "get-relative-luminance": "1.0.0",
@@ -99,8 +101,8 @@
     "markdown-link-check": "3.12.1",
     "mocha": "10.4.0",
     "named-html-entities-json": "1.0.0",
-    "svg-path-bbox": "1.2.6",
-    "svg-path-segments": "2.0.0",
+    "svg-path-bbox": "2.0.0",
+    "svg-path-segments": "2.0.1",
     "svglint": "2.7.1",
     "svgo": "3.2.0",
     "svgpath": "2.6.0",
diff --git a/scripts/add-icon-data.js b/scripts/add-icon-data.js
index 9ee694d31..2719bcdd8 100644
--- a/scripts/add-icon-data.js
+++ b/scripts/add-icon-data.js
@@ -1,4 +1,12 @@
 #!/usr/bin/env node
+/**
+ * @file
+ * Script to add data for a new icon to the simple-icons dataset.
+ */
+
+/**
+ * @typedef {import("../sdk.js").IconData} IconData
+ */
 import process from 'node:process';
 import {ExitPromptError} from '@inquirer/core';
 import {checkbox, confirm, input} from '@inquirer/prompts';
@@ -15,6 +23,7 @@ import {
 } from '../sdk.mjs';
 import {getJsonSchemaData, writeIconsData} from './utils.js';
 
+/** @type {{icons: import('../sdk.js').IconData[]}} */
 const iconsData = JSON.parse(await getIconsDataString());
 const jsonSchema = await getJsonSchemaData();
 
@@ -25,25 +34,42 @@ const aliasTypes = ['aka', 'old'].map((key) => ({
   value: key,
 }));
 
+/** @type {{name: string, value: string}[]} */
 const licenseTypes =
   jsonSchema.definitions.brand.properties.license.oneOf[0].properties.type.enum.map(
-    (license) => ({name: license, value: license}),
+    (/** @type {string} */ license) => ({name: license, value: license}),
   );
 
+/**
+ * @param {string} input URL input
+ * @returns {Promise<boolean|string>} Whether the input is a valid URL
+ */
 const isValidURL = async (input) => {
   const regex = await urlRegex();
   return regex.test(input) || 'Must be a valid and secure (https://) URL.';
 };
 
+/**
+ * @param {string} input Hex color
+ * @returns {boolean|string} Whether the input is a valid hex color
+ */
 const isValidHexColor = (input) =>
   HEX_REGEX.test(input) || 'Must be a valid hex code.';
 
+/**
+ * @param {string} input New icon input
+ * @returns {boolean} Whether the icon is new
+ */
 const isNewIcon = (input) =>
   !iconsData.icons.some(
     (icon) =>
       icon.title === input || titleToSlug(icon.title) === titleToSlug(input),
-  ) || 'This icon title or slug already exists.';
+  );
 
+/**
+ * @param {string} input Color input
+ * @returns {string} Preview of the color
+ */
 const previewHexColor = (input) => {
   const color = normalizeColor(input);
   const luminance = HEX_REGEX.test(input)
@@ -60,7 +86,9 @@ try {
     title: await input({
       message: 'What is the title of this icon?',
       validate: (input) =>
-        input.trim().length > 0 ? isNewIcon(input) : 'This field is required.',
+        input.trim().length > 0
+          ? isNewIcon(input) || 'This icon title or slug already exists.'
+          : 'This field is required.',
     }),
     hex: normalizeColor(
       await input({
@@ -111,6 +139,7 @@ try {
         }).then(async (aliases) => {
           const result = {};
           for (const alias of aliases) {
+            // @ts-ignore
             // eslint-disable-next-line no-await-in-loop
             result[alias] = await input({
               message: `What ${alias} aliases would you like to add? (separate with commas)`,
diff --git a/scripts/build/clean.js b/scripts/build/clean.js
index 83423f25d..ada054674 100644
--- a/scripts/build/clean.js
+++ b/scripts/build/clean.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Clean files built by the build process.
  */
 
diff --git a/scripts/build/package.js b/scripts/build/package.js
index edf737682..2fa563da1 100644
--- a/scripts/build/package.js
+++ b/scripts/build/package.js
@@ -1,9 +1,14 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Simple Icons package build script.
  */
 
+/**
+ * @typedef {import('../../types.js').License} License
+ * @typedef {import('esbuild').TransformOptions} EsBuildTransformOptions
+ */
+
 import {promises as fs} from 'node:fs';
 import path from 'node:path';
 import util from 'node:util';
@@ -36,62 +41,78 @@ const iconObjectTemplateFile = path.resolve(
   'icon-object.js.template',
 );
 
+const icons = await getIconsData();
+const iconObjectTemplate = await fs.readFile(iconObjectTemplateFile, UTF8);
+
+/**
+ * @param {string} value The value to escape
+ * @returns {string} The escaped value
+ */
+const escape = (value) => {
+  return value.replaceAll(/(?<!\\)'/g, "\\'");
+};
+
+/**
+ * @param {License} license The license object or URL
+ * @returns {License} The license object with a URL
+ */
+const licenseToObject = (license) => {
+  if (license.url === undefined) {
+    license.url = `https://spdx.org/licenses/${license.type}`;
+  }
+
+  return license;
+};
+
+// TODO: Find a way to type this object without decreasing performance
+// @ts-ignore
+const iconToJsObject = (icon) => {
+  return util.format(
+    iconObjectTemplate,
+    escape(icon.title),
+    escape(icon.slug),
+    escape(titleToHtmlFriendly(icon.title)),
+    escape(icon.path),
+    escape(icon.source),
+    escape(icon.hex),
+    icon.guidelines ? `\n  guidelines: '${escape(icon.guidelines)}',` : '',
+    icon.license === undefined
+      ? ''
+      : `\n  license: ${JSON.stringify(licenseToObject(icon.license))},`,
+  );
+};
+
+/**
+ * @param {string} filepath The path to the file to write
+ * @param {string} rawJavaScript The raw JavaScript content to write to the file
+ * @param {EsBuildTransformOptions | null} options The options to pass to esbuild
+ */
+const writeJs = async (filepath, rawJavaScript, options = null) => {
+  options = options === null ? {minify: true} : options;
+  const {code} = await esbuildTransform(rawJavaScript, options);
+  await fs.writeFile(filepath, code);
+};
+
+/**
+ * @param {string} filepath The path to the file to write
+ * @param {string} rawTypeScript The raw TypeScript content to write to the file
+ */
+const writeTs = async (filepath, rawTypeScript) => {
+  await fs.writeFile(filepath, rawTypeScript);
+};
+
 const build = async () => {
-  const icons = await getIconsData();
-  const iconObjectTemplate = await fs.readFile(iconObjectTemplateFile, UTF8);
-
-  // Local helper functions
-  const escape = (value) => {
-    return value.replaceAll(/(?<!\\)'/g, "\\'");
-  };
-
-  const licenseToObject = (license) => {
-    if (license === undefined) {
-      return;
-    }
-
-    if (license.url === undefined) {
-      license.url = `https://spdx.org/licenses/${license.type}`;
-    }
-
-    return license;
-  };
-
-  const iconToObject = (icon) => {
-    return util.format(
-      iconObjectTemplate,
-      escape(icon.title),
-      escape(icon.slug),
-      escape(titleToHtmlFriendly(icon.title)),
-      escape(icon.path),
-      escape(icon.source),
-      escape(icon.hex),
-      icon.guidelines ? `\n  guidelines: '${escape(icon.guidelines)}',` : '',
-      licenseToObject(icon.license)
-        ? `\n  license: ${JSON.stringify(licenseToObject(icon.license))},`
-        : '',
-    );
-  };
-
-  const writeJs = async (filepath, rawJavaScript, options = null) => {
-    options = options === null ? {minify: true} : options;
-    const {code} = await esbuildTransform(rawJavaScript, options);
-    await fs.writeFile(filepath, code);
-  };
-
-  const writeTs = async (filepath, rawTypeScript) => {
-    await fs.writeFile(filepath, rawTypeScript);
-  };
-
-  // 'main'
   const buildIcons = await Promise.all(
     icons.map(async (icon) => {
       const filename = getIconSlug(icon);
       const svgFilepath = path.resolve(iconsDirectory, `${filename}.svg`);
+      // TODO: Find a way to type these objects without decreasing performance
+      // @ts-ignore
       icon.svg = await fs.readFile(svgFilepath, UTF8);
+      // @ts-ignore
       icon.path = svgToPath(icon.svg);
       icon.slug = filename;
-      const iconObject = iconToObject(icon);
+      const iconObject = iconToJsObject(icon);
       const iconExportName = slugToVariableName(icon.slug);
       return {icon, iconObject, iconExportName};
     }),
diff --git a/scripts/get-filename.js b/scripts/get-filename.js
index e20f4c123..c55fea2dc 100644
--- a/scripts/get-filename.js
+++ b/scripts/get-filename.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Script that takes a brand name as argument and outputs the corresponding
  * icon SVG filename to standard output.
  */
diff --git a/scripts/lint/jsonlint.js b/scripts/lint/jsonlint.js
index a439bd732..623134256 100644
--- a/scripts/lint/jsonlint.js
+++ b/scripts/lint/jsonlint.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * CLI tool to run jsonschema on the simple-icons.json data file.
  */
 
diff --git a/scripts/lint/ourlint.js b/scripts/lint/ourlint.js
index fcb320498..b76b90b67 100644
--- a/scripts/lint/ourlint.js
+++ b/scripts/lint/ourlint.js
@@ -1,21 +1,39 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Linters for the package that can't easily be implemented in the existing
  * linters (e.g. jsonlint/svglint).
  */
 
+/**
+ * @typedef {import("../../sdk.mjs").IconData} IconData
+ * @typedef {import("../../types.js").CustomLicense} CustomLicense
+ * @typedef {IconData[]} IconsData
+ */
+
 import process from 'node:process';
 import fakeDiff from 'fake-diff';
 import {collator, getIconsDataString, normalizeNewlines} from '../../sdk.mjs';
 
 /**
  * Contains our tests so they can be isolated from each other.
- * @type {{[k:string]: () => (string|undefined)}}
+ * @type {{[k: string]: (arg0: {icons: IconsData}, arg1: string) => string | undefined}}
  */
 const TESTS = {
-  /* Tests whether our icons are in alphabetical order */
+  /**
+   * Tests whether our icons are in alphabetical order
+   * @param {{icons: IconsData}} data Icons data
+   * @returns {string|undefined} Error message or undefined
+   */
   alphabetical(data) {
+    /**
+     * Collects invalid alphabet ordered icons
+     * @param {IconData[]} invalidEntries Invalid icons reference
+     * @param {IconData} icon Icon to check
+     * @param {number} index Index of the icon
+     * @param {IconData[]} array Array of icons
+     * @returns {IconData[]} Invalid icons
+     */
     const collector = (invalidEntries, icon, index, array) => {
       if (index > 0) {
         const previous = array[index - 1];
@@ -34,6 +52,11 @@ const TESTS = {
       return invalidEntries;
     };
 
+    /**
+     * Format an icon for display in the error message
+     * @param {IconData} icon Icon to format
+     * @returns {string} Formatted icon
+     */
     const format = (icon) => {
       if (icon.slug) {
         return `${icon.title} (${icon.slug})`;
@@ -63,6 +86,11 @@ const TESTS = {
 
   /* Check redundant trailing slash in URL */
   checkUrl(data) {
+    /**
+     * Check if an URL has a redundant trailing slash.
+     * @param {string} url URL to check
+     * @returns {boolean} Whether the URL has a redundant trailing slash
+     */
     const hasRedundantTrailingSlash = (url) => {
       const {origin} = new global.URL(url);
       return /^\/+$/.test(url.replace(origin, ''));
@@ -71,7 +99,17 @@ const TESTS = {
     const allUrlFields = [
       ...new Set(
         data.icons
-          .flatMap((icon) => [icon.source, icon.guidelines, icon.license?.url])
+          .flatMap((icon) => {
+            // TODO: `Omit` is not working smoothly here
+            const license =
+              // @ts-ignore
+              icon.license && icon.license.url
+                ? // @ts-ignore
+                  [icon.license.url]
+                : [];
+            return [icon.source, icon.guidelines, ...license];
+          })
+
           .filter(Boolean),
       ),
     ];
@@ -88,11 +126,13 @@ const TESTS = {
   },
 };
 
-const dataString = await getIconsDataString();
-const data = JSON.parse(dataString);
+const iconsDataString = await getIconsDataString();
+const iconsData = JSON.parse(iconsDataString);
 
 const errors = (
-  await Promise.all(Object.values(TESTS).map((test) => test(data, dataString)))
+  await Promise.all(
+    Object.values(TESTS).map((test) => test(iconsData, iconsDataString)),
+  )
 )
   // eslint-disable-next-line unicorn/no-await-expression-member
   .filter(Boolean);
diff --git a/scripts/release/reformat-markdown.js b/scripts/release/reformat-markdown.js
index 8cbc9196d..657f4220e 100644
--- a/scripts/release/reformat-markdown.js
+++ b/scripts/release/reformat-markdown.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Rewrite some Markdown files.
  */
 
@@ -17,6 +17,10 @@ const rootDirectory = path.resolve(__dirname, '..', '..');
 const readmeFile = path.resolve(rootDirectory, 'README.md');
 const disclaimerFile = path.resolve(rootDirectory, 'DISCLAIMER.md');
 
+/**
+ * Reformat a file.
+ * @param {string} filePath Path to the file
+ */
 const reformat = async (filePath) => {
   const fileContent = await readFile(filePath, 'utf8');
   await writeFile(
diff --git a/scripts/release/update-cdn-urls.js b/scripts/release/update-cdn-urls.js
index 38a1f76ea..d436deb78 100644
--- a/scripts/release/update-cdn-urls.js
+++ b/scripts/release/update-cdn-urls.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Updates the CDN URLs in the README.md to match the major version in the
  * NPM package manifest. Does nothing if the README.md is already up-to-date.
  */
@@ -16,16 +16,27 @@ const rootDirectory = path.resolve(__dirname, '..', '..');
 const packageJsonFile = path.resolve(rootDirectory, 'package.json');
 const readmeFile = path.resolve(rootDirectory, 'README.md');
 
+/**
+ * @param {string} semVersion A semantic version string.
+ * @returns {number} The major version number.
+ */
 const getMajorVersion = (semVersion) => {
   const majorVersionAsString = semVersion.split('.')[0];
   return Number.parseInt(majorVersionAsString, 10);
 };
 
+/**
+ * Get the package.json manifest.
+ * @returns {Promise<{version: string}>} The package.json manifest.
+ */
 const getManifest = async () => {
   const manifestRaw = await fs.readFile(packageJsonFile, 'utf8');
   return JSON.parse(manifestRaw);
 };
 
+/**
+ * @param {number} majorVersion The major version number.
+ */
 const updateVersionInReadmeIfNecessary = async (majorVersion) => {
   let content = await fs.readFile(readmeFile, 'utf8');
 
diff --git a/scripts/release/update-sdk-ts-defs.js b/scripts/release/update-sdk-ts-defs.js
index 9856c31e8..049d2f95b 100644
--- a/scripts/release/update-sdk-ts-defs.js
+++ b/scripts/release/update-sdk-ts-defs.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Updates the SDK Typescript definitions located in the file sdk.d.ts
  * to match the current definitions of functions of sdk.mjs.
  */
@@ -34,19 +34,53 @@ const generateSdkMts = async () => {
       'npx tsc sdk.mjs' +
         ' --declaration --emitDeclarationOnly --allowJs --removeComments',
     );
-  } catch (error) {
+  } catch (/** @type {unknown} */ error) {
     await fs.writeFile(sdkMjs, originalSdkMjsContent);
+
+    let errorMessage = error;
+    if (error instanceof Error) {
+      // The `execSync` function throws a generic Node.js Error
+      errorMessage = error.message;
+    }
+
     process.stdout.write(
-      `Error ${error.status} generating Typescript` +
-        ` definitions: '${error.message}'` +
-        '\n',
+      `Error generating Typescript definitions: '${errorMessage}'\n`,
     );
+
     process.exit(1);
   }
 
   await fs.writeFile(sdkMjs, originalSdkMjsContent);
 };
 
+/**
+ * We must remove the duplicated export types that tsc generates from
+ * JSDoc `typedef` comments.
+ * See {@link https://github.com/microsoft/TypeScript/issues/46011}
+ * @param {string} content Content of the file
+ * @returns {string} The content without duplicated export types
+ */
+const removeDuplicatedExportTypes = (content) => {
+  const newContent = [];
+  const lines = content.split('\n');
+  /** @type {string[]} */
+  const exportTypesFound = [];
+
+  for (const line of lines) {
+    if (line.startsWith('export type ')) {
+      const type = line.split(' ')[2];
+      if (!exportTypesFound.includes(type)) {
+        newContent.push(line);
+        exportTypesFound.push(type);
+      }
+    } else {
+      newContent.push(line);
+    }
+  }
+
+  return newContent.join('\n');
+};
+
 const generateSdkTs = async () => {
   const fileExists = await fs
     .access(sdkMts)
@@ -62,15 +96,21 @@ const generateSdkTs = async () => {
     (await fs.readFile(sdkTs, 'utf8')).split(autogeneratedMessage)[0] +
     `${autogeneratedMessage}\n\n${await fs.readFile(sdkMts, 'utf8')}`;
 
-  await fs.writeFile(sdkTs, newSdkTsContent);
+  await fs.writeFile(sdkTs, removeDuplicatedExportTypes(newSdkTsContent));
   await fs.unlink(sdkMts);
 
   try {
     execSync('npx prettier -w sdk.d.ts');
   } catch (error) {
+    let errorMessage = error;
+    if (error instanceof Error) {
+      // The `execSync` function throws a generic Node.js Error
+      errorMessage = error.message;
+    }
+
     process.stdout.write(
-      `Error ${error.status} executing Prettier` +
-        ` to prettify SDK TS definitions: '${error.message}'` +
+      'Error executing Prettier to prettify' +
+        ` SDK TS definitions: '${errorMessage}'` +
         '\n',
     );
     process.exit(1);
diff --git a/scripts/release/update-slugs-table.js b/scripts/release/update-slugs-table.js
index 74f61dbaa..7b3734bfa 100644
--- a/scripts/release/update-slugs-table.js
+++ b/scripts/release/update-slugs-table.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Generates a MarkDown file that lists every brand name and their slug.
  */
 
diff --git a/scripts/release/update-svgs-count.js b/scripts/release/update-svgs-count.js
index b90f7af1c..5ce295237 100644
--- a/scripts/release/update-svgs-count.js
+++ b/scripts/release/update-svgs-count.js
@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 /**
- * @fileoverview
+ * @file
  * Replaces the SVG count milestone "Over <NUMBER> Free SVG icons..." located
  * at README every time the number of current icons is more than `updateRange`
  * more than the previous milestone.
@@ -20,22 +20,32 @@ const readmeFile = path.resolve(rootDirectory, 'README.md');
 
 const readmeContent = await fs.readFile(readmeFile, 'utf8');
 
-let overNIconsInReadme;
 try {
-  overNIconsInReadme = Number.parseInt(regexMatcher.exec(readmeContent)[1], 10);
+  const match = regexMatcher.exec(readmeContent);
+  if (match === null) {
+    console.error(
+      'Failed to obtain number of SVG icons of current milestone in README:',
+      'No match found',
+    );
+    process.exit(1);
+  } else {
+    const overNIconsInReadme = Number.parseInt(match[1], 10);
+    const iconsData = await getIconsData();
+    const nIcons = iconsData.length;
+    const newNIcons = overNIconsInReadme + updateRange;
+
+    if (nIcons > newNIcons) {
+      const newContent = readmeContent.replace(
+        regexMatcher,
+        `Over ${newNIcons} `,
+      );
+      await fs.writeFile(readmeFile, newContent);
+    }
+  }
 } catch (error) {
   console.error(
-    'Failed to obtain number of SVG icons of current milestone in README:',
+    'Failed to update number of SVG icons of current milestone in README:',
     error,
   );
   process.exit(1);
 }
-
-const iconsData = await getIconsData();
-const nIcons = iconsData.length;
-const newNIcons = overNIconsInReadme + updateRange;
-
-if (nIcons > newNIcons) {
-  const newContent = readmeContent.replace(regexMatcher, `Over ${newNIcons} `);
-  await fs.writeFile(readmeFile, newContent);
-}
diff --git a/scripts/utils.js b/scripts/utils.js
index 474a4ba4a..ca5680166 100644
--- a/scripts/utils.js
+++ b/scripts/utils.js
@@ -1,12 +1,24 @@
+/**
+ * @file Internal utilities.
+ *
+ * Here resides all the functionality that does not qualifies to reside
+ * in the SDK because is not publicly exposed.
+ */
+
 import fs from 'node:fs/promises';
 import path from 'node:path';
 import {getDirnameFromImportMeta, getIconDataPath} from '../sdk.mjs';
 
 const __dirname = getDirnameFromImportMeta(import.meta.url);
 
+/**
+ * @typedef {import("../sdk.js").IconData} IconData
+ */
+
 /**
  * Get JSON schema data.
- * @param {String} rootDirectory Path to the root directory of the project.
+ * @param {string} rootDirectory Path to the root directory of the project.
+ * @returns {Promise<any>} JSON schema data.
  */
 export const getJsonSchemaData = async (
   rootDirectory = path.resolve(__dirname, '..'),
@@ -18,8 +30,8 @@ export const getJsonSchemaData = async (
 
 /**
  * Write icons data to _data/simple-icons.json.
- * @param {Object} iconsData Icons data object.
- * @param {String} rootDirectory Path to the root directory of the project.
+ * @param {{icons: IconData[]}} iconsData Icons data object.
+ * @param {string} rootDirectory Path to the root directory of the project.
  */
 export const writeIconsData = async (
   iconsData,
diff --git a/sdk.d.ts b/sdk.d.ts
index 184fe2283..4ad8726f4 100644
--- a/sdk.d.ts
+++ b/sdk.d.ts
@@ -1,5 +1,5 @@
 /**
- * @fileoverview
+ * @file
  * Types for Simple Icons SDK.
  */
 
@@ -10,7 +10,6 @@ import type {CustomLicense, SPDXLicense} from './types';
  *
  * Includes the module and author of the extension,
  * both including a name and URL.
- *
  * @see {@link https://github.com/simple-icons/simple-icons#third-party-extensions Third-Party Extensions}
  */
 export type ThirdPartyExtension = {
@@ -27,7 +26,6 @@ type ThirdPartyExtensionSubject = {
  * The aliases for a Simple Icon.
  *
  * Corresponds to the `aliases` property in the *_data/simple-icons.json* file.
- *
  * @see {@link https://github.com/simple-icons/simple-icons/blob/develop/CONTRIBUTING.md#aliases Aliases}
  */
 export type Aliases = {
@@ -47,7 +45,6 @@ type DuplicateAlias = {
  * The data for a Simple Icon.
  *
  * Corresponds to the data stored for each icon in the *_data/simple-icons.json* file.
- *
  * @see {@link https://github.com/mondeja/simple-icons/blob/utils-entrypoint/CONTRIBUTING.md#7-update-the-json-data-for-simpleiconsorg Update the JSON Data for SimpleIcons.org}
  */
 export type IconData = {
@@ -73,8 +70,8 @@ export function slugToVariableName(slug: string): string;
 export function titleToHtmlFriendly(brandTitle: string): string;
 export function htmlFriendlyToTitle(htmlFriendlyTitle: string): string;
 export function getIconDataPath(rootDirectory?: string): string;
-export function getIconsDataString(rootDirectory?: string): string;
-export function getIconsData(rootDirectory?: string): IconData[];
+export function getIconsDataString(rootDirectory?: string): Promise<string>;
+export function getIconsData(rootDirectory?: string): Promise<IconData[]>;
 export function normalizeNewlines(text: string): string;
 export function normalizeColor(text: string): string;
 export function getThirdPartyExtensions(
diff --git a/sdk.mjs b/sdk.mjs
index 0fa791075..426773aff 100644
--- a/sdk.mjs
+++ b/sdk.mjs
@@ -1,5 +1,5 @@
 /**
- * @fileoverview
+ * @file
  * Simple Icons SDK.
  */
 
@@ -8,10 +8,11 @@ import path from 'node:path';
 import {fileURLToPath} from 'node:url';
 
 /**
- * @typedef {import("./sdk").ThirdPartyExtension} ThirdPartyExtension
- * @typedef {import("./sdk").IconData} IconData
+ * @typedef {import("./sdk.d.ts").ThirdPartyExtension} ThirdPartyExtension
+ * @typedef {import("./sdk.d.ts").IconData} IconData
  */
 
+/** @type {{ [key: string]: string }} */
 const TITLE_TO_SLUG_REPLACEMENTS = {
   '+': 'plus',
   '.': 'dot',
@@ -41,15 +42,15 @@ export const SVG_PATH_REGEX = /^m[-mzlhvcsqtae\d,. ]+$/i;
 /**
  * Get the directory name where this file is located from `import.meta.url`,
  * equivalent to the `__dirname` global variable in CommonJS.
- * @param {String} importMetaUrl import.meta.url
- * @returns {String} Directory name in which this file is located
+ * @param {string} importMetaUrl import.meta.url
+ * @returns {string} Directory name in which this file is located
  */
 export const getDirnameFromImportMeta = (importMetaUrl) =>
   path.dirname(fileURLToPath(importMetaUrl));
 
 /**
  * Build a regex to validate HTTPs URLs.
- * @param {String} jsonschemaPath Path to the *.jsonschema.json* file
+ * @param {string} jsonschemaPath Path to the *.jsonschema.json* file
  * @returns {Promise<RegExp>} Regex to validate HTTPs URLs
  */
 export const urlRegex = async (
@@ -68,21 +69,21 @@ export const urlRegex = async (
 /**
  * Get the slug/filename for an icon.
  * @param {IconData} icon The icon data as it appears in *_data/simple-icons.json*
- * @returns {String} The slug/filename for the icon
+ * @returns {string} The slug/filename for the icon
  */
 export const getIconSlug = (icon) => icon.slug || titleToSlug(icon.title);
 
 /**
  * Extract the path from an icon SVG content.
- * @param {String} svg The icon SVG content
- * @returns {String} The path from the icon SVG content
- **/
+ * @param {string} svg The icon SVG content
+ * @returns {string} The path from the icon SVG content
+ */
 export const svgToPath = (svg) => svg.split('"', 8)[7];
 
 /**
  * Converts a brand title into a slug/filename.
- * @param {String} title The title to convert
- * @returns {String} The slug/filename for the title
+ * @param {string} title The title to convert
+ * @returns {string} The slug/filename for the title
  */
 export const titleToSlug = (title) =>
   title
@@ -96,8 +97,8 @@ export const titleToSlug = (title) =>
 
 /**
  * Converts a slug into a variable name that can be exported.
- * @param {String} slug The slug to convert
- * @returns {String} The variable name for the slug
+ * @param {string} slug The slug to convert
+ * @returns {string} The variable name for the slug
  */
 export const slugToVariableName = (slug) => {
   const slugFirstLetter = slug[0].toUpperCase();
@@ -107,8 +108,8 @@ export const slugToVariableName = (slug) => {
 /**
  * Converts a brand title as defined in *_data/simple-icons.json* into a brand
  * title in HTML/SVG friendly format.
- * @param {String} brandTitle The title to convert
- * @returns {String} The brand title in HTML/SVG friendly format
+ * @param {string} brandTitle The title to convert
+ * @returns {string} The brand title in HTML/SVG friendly format
  */
 export const titleToHtmlFriendly = (brandTitle) =>
   brandTitle
@@ -117,6 +118,8 @@ export const titleToHtmlFriendly = (brandTitle) =>
     .replaceAll('<', '&lt;')
     .replaceAll('>', '&gt;')
     .replaceAll(/./g, (char) => {
+      /** @type {number} */
+      // @ts-ignore
       const charCode = char.codePointAt(0);
       return charCode > 127 ? `&#${charCode};` : char;
     });
@@ -124,8 +127,8 @@ export const titleToHtmlFriendly = (brandTitle) =>
 /**
  * Converts a brand title in HTML/SVG friendly format into a brand title (as
  * it is seen in *_data/simple-icons.json*)
- * @param {String} htmlFriendlyTitle The title to convert
- * @returns {String} The brand title in HTML/SVG friendly format
+ * @param {string} htmlFriendlyTitle The title to convert
+ * @returns {string} The brand title in HTML/SVG friendly format
  */
 export const htmlFriendlyToTitle = (htmlFriendlyTitle) =>
   htmlFriendlyTitle
@@ -134,13 +137,18 @@ export const htmlFriendlyToTitle = (htmlFriendlyTitle) =>
     )
     .replaceAll(
       /&(quot|amp|lt|gt);/g,
+      /**
+       * @param {string} _ Full match
+       * @param {'quot' | 'amp' | 'lt' | 'gt'} reference Reference to replace
+       * @returns {string} Replacement for the reference
+       */
       (_, reference) => ({quot: '"', amp: '&', lt: '<', gt: '>'})[reference],
     );
 
 /**
  * Get path of *_data/simple-icons.json*.
- * @param {String} rootDirectory Path to the root directory of the project
- * @returns {String} Path of *_data/simple-icons.json*
+ * @param {string} rootDirectory Path to the root directory of the project
+ * @returns {string} Path of *_data/simple-icons.json*
  */
 export const getIconDataPath = (
   rootDirectory = getDirnameFromImportMeta(import.meta.url),
@@ -150,8 +158,8 @@ export const getIconDataPath = (
 
 /**
  * Get contents of *_data/simple-icons.json*.
- * @param {String} rootDirectory Path to the root directory of the project
- * @returns {String} Content of *_data/simple-icons.json*
+ * @param {string} rootDirectory Path to the root directory of the project
+ * @returns {Promise<string>} Content of *_data/simple-icons.json*
  */
 export const getIconsDataString = (
   rootDirectory = getDirnameFromImportMeta(import.meta.url),
@@ -161,8 +169,8 @@ export const getIconsDataString = (
 
 /**
  * Get icons data as object from *_data/simple-icons.json*.
- * @param {String} rootDirectory Path to the root directory of the project
- * @returns {IconData[]} Icons data as array from *_data/simple-icons.json*
+ * @param {string} rootDirectory Path to the root directory of the project
+ * @returns {Promise<IconData[]>} Icons data as array from *_data/simple-icons.json*
  */
 export const getIconsData = async (
   rootDirectory = getDirnameFromImportMeta(import.meta.url),
@@ -173,8 +181,8 @@ export const getIconsData = async (
 
 /**
  * Replace Windows newline characters by Unix ones.
- * @param {String} text The text to replace
- * @returns {String} The text with Windows newline characters replaced by Unix ones
+ * @param {string} text The text to replace
+ * @returns {string} The text with Windows newline characters replaced by Unix ones
  */
 export const normalizeNewlines = (text) => {
   return text.replaceAll('\r\n', '\n');
@@ -182,8 +190,8 @@ export const normalizeNewlines = (text) => {
 
 /**
  * Convert non-6-digit hex color to 6-digit with the character `#` stripped.
- * @param {String} text The color text
- * @returns {String} The color text in 6-digit hex format
+ * @param {string} text The color text
+ * @returns {string} The color text in 6-digit hex format
  */
 export const normalizeColor = (text) => {
   let color = text.replace('#', '').toUpperCase();
@@ -199,7 +207,7 @@ export const normalizeColor = (text) => {
 
 /**
  * Get information about third party extensions from the README table.
- * @param {String} readmePath Path to the README file
+ * @param {string} readmePath Path to the README file
  * @returns {Promise<ThirdPartyExtension[]>} Information about third party extensions
  */
 export const getThirdPartyExtensions = async (
@@ -214,23 +222,43 @@ export const getThirdPartyExtensions = async (
     .split('|\n|')
     .slice(2)
     .map((line) => {
-      let [module, author] = line.split(' | ');
-      module = module.split('<img src="')[0];
+      const [module_, author] = line.split(' | ');
+      const module = module_.split('<img src="')[0];
+      const moduleName = /\[(.+)]/.exec(module)?.[1];
+      if (moduleName === undefined) {
+        throw new Error(`Module name improperly parsed from line: ${line}`);
+      }
+
+      const moduleUrl = /\((.+)\)/.exec(module)?.[1];
+      if (moduleUrl === undefined) {
+        throw new Error(`Module URL improperly parsed from line: ${line}`);
+      }
+
+      const authorName = /\[(.+)]/.exec(author)?.[1];
+      if (authorName === undefined) {
+        throw new Error(`Author improperly parsed from line: ${line}`);
+      }
+
+      const authorUrl = /\((.+)\)/.exec(author)?.[1];
+      if (authorUrl === undefined) {
+        throw new Error(`Author URL improperly parsed from line: ${line}`);
+      }
+
       return {
         module: {
-          name: /\[(.+)]/.exec(module)[1],
-          url: /\((.+)\)/.exec(module)[1],
+          name: moduleName,
+          url: moduleUrl,
         },
         author: {
-          name: /\[(.+)]/.exec(author)[1],
-          url: /\((.+)\)/.exec(author)[1],
+          name: authorName,
+          url: authorUrl,
         },
       };
     });
 
 /**
  * Get information about third party libraries from the README table.
- * @param {String} readmePath Path to the README file
+ * @param {string} readmePath Path to the README file
  * @returns {Promise<ThirdPartyExtension[]>} Information about third party libraries
  */
 export const getThirdPartyLibraries = async (
@@ -247,23 +275,42 @@ export const getThirdPartyLibraries = async (
     .map((line) => {
       let [module, author] = line.split(' | ');
       module = module.split('<img src="')[0];
+      const moduleName = /\[(.+)]/.exec(module)?.[1];
+      if (moduleName === undefined) {
+        throw new Error(`Module name improperly parsed from line: ${line}`);
+      }
+
+      const moduleUrl = /\((.+)\)/.exec(module)?.[1];
+      if (moduleUrl === undefined) {
+        throw new Error(`Module URL improperly parsed from line: ${line}`);
+      }
+
+      const authorName = /\[(.+)]/.exec(author)?.[1];
+      if (authorName === undefined) {
+        throw new Error(`Author improperly parsed from line: ${line}`);
+      }
+
+      const authorUrl = /\((.+)\)/.exec(author)?.[1];
+      if (authorUrl === undefined) {
+        throw new Error(`Author URL improperly parsed from line: ${line}`);
+      }
+
       return {
         module: {
-          name: /\[(.+)]/.exec(module)[1],
-          url: /\((.+)\)/.exec(module)[1],
+          name: moduleName,
+          url: moduleUrl,
         },
         author: {
-          name: /\[(.+)]/.exec(author)[1],
-          url: /\((.+)\)/.exec(author)[1],
+          name: authorName,
+          url: authorUrl,
         },
       };
     });
 
 /**
  * `Intl.Collator` object ready to be used for icon titles sorting.
- * @type {Intl.Collator}
- * @see {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Collator Intl.Collator}
- **/
+ * @see {@link https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Intl/Collator Intl.Collator}
+ */
 export const collator = new Intl.Collator('en', {
   usage: 'search',
   caseFirst: 'upper',
diff --git a/svglint.config.mjs b/svglint.config.mjs
index 966d023f7..82eb0b2fc 100644
--- a/svglint.config.mjs
+++ b/svglint.config.mjs
@@ -1,8 +1,12 @@
-/* eslint complexity: off, max-depth: off */
+/**
+ * @file
+ * Linting rules for SVGLint to check SVG icons.
+ */
+
 import fs from 'node:fs/promises';
 import path from 'node:path';
 import process from 'node:process';
-import svgPathBbox from 'svg-path-bbox';
+import {svgPathBbox} from 'svg-path-bbox';
 import parsePath from 'svg-path-segments';
 import svgpath from 'svgpath';
 import {
@@ -26,6 +30,7 @@ const icons = await getIconsData();
 const htmlNamedEntities = JSON.parse(
   await fs.readFile(htmlNamedEntitiesFile, 'utf8'),
 );
+/** @type {{ [key: string]: { [key: string]: string } }} */
 const svglintIgnores = JSON.parse(
   await fs.readFile(svglintIgnoredFile, 'utf8'),
 );
@@ -45,6 +50,10 @@ const updateIgnoreFile = process.env.SI_UPDATE_IGNORE === 'true';
 const ignoreFile = './.svglint-ignored.json';
 const iconIgnored = updateIgnoreFile ? {} : svglintIgnores;
 
+/**
+ * @param {{ [key: string]: any }} object Object to sort by key
+ * @returns {{ [key: string]: any }} Object sorted by key
+ */
 const sortObjectByKey = (object) => {
   return Object.fromEntries(
     Object.keys(object)
@@ -53,6 +62,10 @@ const sortObjectByKey = (object) => {
   );
 };
 
+/**
+ * @param {{ [key: string]: any }} object Object to sort by value
+ * @returns {{ [key: string]: any }} Object sorted by value
+ */
 const sortObjectByValue = (object) => {
   return Object.fromEntries(
     Object.keys(object)
@@ -61,15 +74,27 @@ const sortObjectByValue = (object) => {
   );
 };
 
-const removeLeadingZeros = (number) => {
+/**
+ * Remove leading zeros from a number as a string.
+ * @param {number | string} numberOrString The number or string to remove leading zeros from.
+ * @returns {string} The number as a string without leading zeros.
+ */
+const removeLeadingZeros = (numberOrString) => {
   // Convert 0.03 to '.03'
-  return number.toString().replace(/^(-?)(0)(\.?.+)/, '$1$3');
+  return numberOrString.toString().replace(/^(-?)(0)(\.?.+)/, '$1$3');
 };
 
 /**
  * Given three points, returns if the middle one (x2, y2) is collinear
  *   to the line formed by the two limit points.
- **/
+ * @param {number} x1 The x coordinate of the first point.
+ * @param {number} y1 The y coordinate of the first point.
+ * @param {number} x2 The x coordinate of the second point.
+ * @param {number} y2 The y coordinate of the second point.
+ * @param {number} x3 The x coordinate of the third point.
+ * @param {number} y3 The y coordinate of the third point.
+ * @returns {boolean} Whether the middle point is collinear to the line.
+ */
 // eslint-disable-next-line max-params
 const collinear = (x1, y1, x2, y2, x3, y3) => {
   return x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2) === 0;
@@ -77,7 +102,8 @@ const collinear = (x1, y1, x2, y2, x3, y3) => {
 
 /**
  * Returns the number of digits after the decimal point.
- * @param num The number of interest.
+ * @param {number} number_ The number to count the decimals of.
+ * @returns {number} The number of digits after the decimal point.
  */
 const countDecimals = (number_) => {
   if (number_ && number_ % 1) {
@@ -94,7 +120,8 @@ const countDecimals = (number_) => {
 
 /**
  * Get the index at which the first path value of an SVG starts.
- * @param svgFileContent The raw SVG as text.
+ * @param {string} svgFileContent The raw SVG as text.
+ * @returns {number} The index at which the path value starts.
  */
 const getPathDIndex = (svgFileContent) => {
   const pathDStart = '<path d="';
@@ -103,8 +130,9 @@ const getPathDIndex = (svgFileContent) => {
 
 /**
  * Get the index at which the text of the first `<title></title>` tag starts.
- * @param svgFileContent The raw SVG as text.
- **/
+ * @param {string} svgFileContent The raw SVG as text.
+ * @returns {number} The index at which the title text starts.
+ */
 const getTitleTextIndex = (svgFileContent) => {
   const titleStart = '<title>';
   return svgFileContent.indexOf(titleStart) + titleStart.length;
@@ -112,8 +140,9 @@ const getTitleTextIndex = (svgFileContent) => {
 
 /**
  * Convert a hexadecimal number passed as string to decimal number as integer.
- * @param hex The hexadecimal number representation to convert.
- **/
+ * @param {string} hex The hexadecimal number representation to convert.
+ * @returns {number} The decimal number representation.
+ */
 const hexadecimalToDecimal = (hex) => {
   let result = 0;
   let digitValue;
@@ -125,6 +154,11 @@ const hexadecimalToDecimal = (hex) => {
   return result;
 };
 
+/**
+ * Shorten a string with ellipsis if it exceeds 20 characters.
+ * @param {string} string_ The string to shorten.
+ * @returns {string} The shortened string.
+ */
 const maybeShortenedWithEllipsis = (string_) => {
   return string_.length > 20 ? `${string_.slice(0, 20)}...` : string_;
 };
@@ -132,21 +166,32 @@ const maybeShortenedWithEllipsis = (string_) => {
 /**
  * Memoize a function which accepts a single argument.
  * A second argument can be passed to be used as key.
+ * @param {(arg0: any) => any} function_ The function to memoize.
+ * @returns {(arg0: any) => any} The memoized function.
  */
 const memoize = (function_) => {
+  /** @type {{ [key: string]: any }} */
   const results = {};
 
-  return (argument, defaultKey = null) => {
-    const key = defaultKey || argument;
+  /**
+   * Memoized function.
+   * @param {any} argument The argument to memoize.
+   * @returns {any} The result of the memoized function.
+   */
+  return (argument) => {
+    results[argument] ||= function_(argument);
 
-    results[key] ||= function_(argument);
-
-    return results[key];
+    return results[argument];
   };
 };
 
-const getIconPath = memoize(($icon, _filepath) => $icon.find('path').attr('d'));
+/** @typedef {import('cheerio').Cheerio<import('domhandler').Document>} Cheerio */
+
+/** @type {($icon: Cheerio) => string} */
+const getIconPath = memoize(($icon) => $icon.find('path').attr('d'));
+/** @type {(iconPath: string) => import('svg-path-segments').Segment[]} */
 const getIconPathSegments = memoize((iconPath) => parsePath(iconPath));
+/** @type {(iconPath: string) => import('svg-path-bbox').BBox} */
 const getIconPathBbox = memoize((iconPath) => svgPathBbox(iconPath));
 
 if (updateIgnoreFile) {
@@ -165,21 +210,34 @@ if (updateIgnoreFile) {
   });
 }
 
-const isIgnored = (linterName, path) => {
+/**
+ * Check if an icon is ignored by a linter rule.
+ * @param {string} linterRule The name of the linter rule.
+ * @param {string} path SVG path of the icon.
+ * @returns {boolean} Whether the icon is ignored by the linter rule
+ */
+const isIgnored = (linterRule, path) => {
   return (
-    iconIgnored[linterName] && Object.hasOwn(iconIgnored[linterName], path)
+    iconIgnored[linterRule] && Object.hasOwn(iconIgnored[linterRule], path)
   );
 };
 
-const ignoreIcon = (linterName, path, $) => {
-  iconIgnored[linterName] ||= {};
+/**
+ * Ignore an icon for a linter rule.
+ * @param {string} linterRule The name of the linter rule.
+ * @param {string} path SVG path of the icon.
+ * @param {Cheerio} $ The SVG object
+ */
+const ignoreIcon = (linterRule, path, $) => {
+  iconIgnored[linterRule] ||= {};
 
   const title = $.find('title').text();
   const iconName = htmlFriendlyToTitle(title);
 
-  iconIgnored[linterName][path] = iconName;
+  iconIgnored[linterRule][path] = iconName;
 };
 
+/** @type {import('svglint').Config} */
 const config = {
   rules: {
     elm: {
@@ -213,6 +271,7 @@ const config = {
       },
     ],
     custom: [
+      // eslint-disable-next-line complexity
       (reporter, $, ast) => {
         reporter.name = 'icon-title';
 
@@ -307,6 +366,8 @@ const config = {
               encodedBuf.unshift(iconTitleText[i]);
             } else {
               // Encode all non ascii characters plus "'&<> (XML named entities)
+              /** @type {number} */
+              // @ts-ignore Coerce to number
               const charDecimalCode = iconTitleText.codePointAt(i);
 
               if (charDecimalCode > 127) {
@@ -337,8 +398,12 @@ const config = {
 
           // Check if there are some other encoded characters in decimal notation
           // which shouldn't be encoded
-          // eslint-disable-next-line unicorn/prefer-number-properties
-          for (const match of encodingMatches.filter((m) => !isNaN(m[2]))) {
+          for (const match of encodingMatches.filter((m) => {
+            // TODO: this fails using `Number.isNaN`, investigate
+            // @ts-ignore
+            // eslint-disable-next-line unicorn/prefer-number-properties
+            return !isNaN(m[2]);
+          })) {
             const decimalNumber = Number.parseInt(match[2], 10);
             if (decimalNumber > 127) {
               continue;
@@ -378,10 +443,10 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $) => {
         reporter.name = 'icon-size';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         if (!updateIgnoreFile && isIgnored(reporter.name, iconPath)) {
           return;
         }
@@ -407,16 +472,19 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'icon-precision';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         const segments = getIconPathSegments(iconPath);
 
         for (const segment of segments) {
+          /** @type {number[]} */
+          // @ts-ignore
+          const numberParameters = segment.params.slice(1);
           const precisionMax = Math.max(
             // eslint-disable-next-line unicorn/no-array-callback-reference
-            ...segment.params.slice(1).map(countDecimals),
+            ...numberParameters.map(countDecimals),
           );
           if (precisionMax > iconMaxFloatPrecision) {
             let errorMessage =
@@ -439,11 +507,16 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'ineffective-segments';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         const segments = getIconPathSegments(iconPath);
+
+        /** @type {import('svg-path-segments').Segment[]} */
+        // TODO: svgpath does not includes the segment property on the interface,
+        //       see https://github.com/fontello/svgpath/pull/67/files
+        // @ts-ignore
         const absSegments = svgpath(iconPath).abs().unshort().segments;
 
         const lowerMovementCommands = ['m', 'l'];
@@ -476,11 +549,16 @@ const config = {
           ...curveCommands,
         ]);
 
-        const isInvalidSegment = (
-          [command, x1Coord, y1Coord, ...rest],
-          index,
-          previousSegmentIsZ,
-        ) => {
+        /**
+         * Check if a segment is ineffective.
+         * @param {import('svg-path-segments').Segment} segment The segment to check.
+         * @param {number} index The index of the segment in the path.
+         * @param {boolean} previousSegmentIsZ Whether the previous segment is a Z command.
+         * @returns {boolean} Whether the segment is ineffective.
+         */
+        // eslint-disable-next-line complexity
+        const isInvalidSegment = (segment, index, previousSegmentIsZ) => {
+          const [command, x1Coord, y1Coord, ...rest] = segment.params;
           if (commands.has(command)) {
             // Relative directions (h or v) having a length of 0
             if (lowerDirectionCommands.includes(command) && x1Coord === 0) {
@@ -534,6 +612,7 @@ const config = {
                   let [yPreviousCoordDeep, xPreviousCoordDeep] = [
                     ...absSegments[index_],
                   ].reverse();
+
                   // If the previous command was a horizontal movement,
                   // we need to consider the single coordinate as x
                   if (upperHorDirectionCommand === xPreviousCoordDeep) {
@@ -609,6 +688,8 @@ const config = {
               );
             }
           }
+
+          return false;
         };
 
         for (let index = 0; index < segments.length; index++) {
@@ -616,7 +697,7 @@ const config = {
           const previousSegmentIsZ =
             index > 0 && segments[index - 1].params[0].toLowerCase() === 'z';
 
-          if (isInvalidSegment(segment.params, index, previousSegmentIsZ)) {
+          if (isInvalidSegment(segment, index, previousSegmentIsZ)) {
             const [command, _x1, _y1, ...rest] = segment.params;
 
             let errorMessage = `Ineffective segment "${iconPath.slice(
@@ -671,13 +752,15 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'collinear-segments';
-
         /**
          * Extracts collinear coordinates from SVG path straight lines
-         *   (does not extracts collinear coordinates from curves).
-         **/
+         * (does not extracts collinear coordinates from curves).
+         * @param {string} iconPath The SVG path of the icon.
+         * @returns {import('svg-path-segments').Segment[]} The collinear segments.
+         */
+        // eslint-disable-next-line complexity
         const getCollinearSegments = (iconPath) => {
           const segments = getIconPathSegments(iconPath);
           const collinearSegments = [];
@@ -694,13 +777,18 @@ const config = {
             const seg = segments[s];
             const parms = seg.params;
             const cmd = parms[0];
-            const nextCmd = s + 1 < segments.length ? segments[s + 1][0] : null;
+            const nextCmd =
+              s + 1 < segments.length ? segments[s + 1].params[0] : null;
 
             switch (cmd) {
               // Next switch cases have been ordered by frequency
               // of occurrence in the SVG paths of the icons
               case 'M': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[2];
                 // SVG 1.1:
                 // If a moveto is followed by multiple pairs of coordinates,
@@ -713,7 +801,11 @@ const config = {
               }
 
               case 'm': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[2];
                 if (seg.chain === undefined || seg.chain.start === seg.start) {
                   startPoint = undefined;
@@ -723,33 +815,49 @@ const config = {
               }
 
               case 'H': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[1];
                 break;
               }
 
               case 'h': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[1];
                 break;
               }
 
               case 'V': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[1];
                 break;
               }
 
               case 'v': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[1];
                 break;
               }
 
               case 'L': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[2];
                 break;
               }
 
               case 'l': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[2];
                 break;
               }
@@ -763,61 +871,101 @@ const config = {
               }
 
               case 'C': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[5];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[6];
                 break;
               }
 
               case 'c': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[5];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[6];
                 break;
               }
 
               case 'A': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[6];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[7];
                 break;
               }
 
               case 'a': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[6];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[7];
                 break;
               }
 
               case 's': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[2];
                 break;
               }
 
               case 'S': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[2];
                 break;
               }
 
               case 't': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[2];
                 break;
               }
 
               case 'T': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[1];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[2];
                 break;
               }
 
               case 'Q': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = parms[3];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = parms[4];
                 break;
               }
 
               case 'q': {
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[0] = (currentAbsCoord[0] || 0) + parms[3];
+                /** @type {number} */
+                // @ts-ignore
                 currentAbsCoord[1] = (currentAbsCoord[1] || 0) + parms[4];
                 break;
               }
@@ -872,7 +1020,7 @@ const config = {
           return collinearSegments;
         };
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         const collinearSegments = getCollinearSegments(iconPath);
         if (collinearSegments.length === 0) {
           return;
@@ -913,10 +1061,10 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'negative-zeros';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
 
         // Find negative zeros inside path
         const negativeZeroMatches = [...iconPath.matchAll(negativeZerosRegexp)];
@@ -937,10 +1085,10 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $) => {
         reporter.name = 'icon-centered';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         if (!updateIgnoreFile && isIgnored(reporter.name, iconPath)) {
           return;
         }
@@ -964,15 +1112,17 @@ const config = {
           }
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'final-closepath';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
         const segments = getIconPathSegments(iconPath);
 
         // Unnecessary characters after the final closepath
+        /** @type {import('svg-path-segments').Segment} */
+        // @ts-ignore
         const lastSegment = segments.at(-1);
-        const endsWithZ = ['z', 'Z'].includes(lastSegment.params.at(0));
+        const endsWithZ = ['z', 'Z'].includes(lastSegment.params[0]);
         if (endsWithZ && lastSegment.end - lastSegment.start > 1) {
           const ending = iconPath.slice(lastSegment.start + 1);
           const closepath = iconPath.at(lastSegment.start);
@@ -985,10 +1135,10 @@ const config = {
           reporter.error(errorMessage);
         }
       },
-      (reporter, $, ast, {filepath}) => {
+      (reporter, $, ast) => {
         reporter.name = 'path-format';
 
-        const iconPath = getIconPath($, filepath);
+        const iconPath = getIconPath($);
 
         if (!SVG_PATH_REGEX.test(iconPath)) {
           const errorMessage = 'Invalid path format';
diff --git a/svgo.config.mjs b/svgo.config.mjs
index f3e99960e..60ec75968 100644
--- a/svgo.config.mjs
+++ b/svgo.config.mjs
@@ -1,6 +1,10 @@
+/**
+ * @file SVGO configuration for Simple Icons.
+ */
+
+/** @type {import("svgo").Config} */
 const config = {
   multipass: true,
-  eol: 'lf',
   plugins: [
     'cleanupAttrs',
     'inlineStyles',
@@ -72,7 +76,6 @@ const config = {
       name: 'sortAttrs',
       params: {
         order: ['role', 'viewBox', 'xmlns'],
-        xmlnsOrder: 'end',
       },
     },
     'sortDefsChildren',
@@ -87,7 +90,6 @@ const config = {
         ],
       },
     },
-    'removeElementsByAttr',
     {
       // Keep the role="img" attribute and automatically add it
       // to the <svg> tag if it's not there already
diff --git a/tests/docs.test.js b/tests/docs.test.js
index 9c5afeca6..ab4fa3735 100644
--- a/tests/docs.test.js
+++ b/tests/docs.test.js
@@ -1,3 +1,7 @@
+/**
+ * @file Tests for the documentation.
+ */
+
 import {strict as assert} from 'node:assert';
 import {test} from 'mocha';
 import {getThirdPartyExtensions, getThirdPartyLibraries} from '../sdk.mjs';
diff --git a/tests/index.test.js b/tests/index.test.js
index 2b10b96f8..ad3552fa8 100644
--- a/tests/index.test.js
+++ b/tests/index.test.js
@@ -1,3 +1,9 @@
+/**
+ * @file Tests for the index file of npm package.
+ */
+
+// The index.mjs file is generated on build before running tests
+// @ts-ignore
 import * as simpleIcons from '../index.mjs';
 import {getIconSlug, getIconsData, slugToVariableName} from '../sdk.mjs';
 import {testIcon} from './test-icon.js';
@@ -5,6 +11,8 @@ import {testIcon} from './test-icon.js';
 for (const icon of await getIconsData()) {
   const slug = getIconSlug(icon);
   const variableName = slugToVariableName(slug);
+  /** @type {import('../types.d.ts').SimpleIcon} */
+  // @ts-ignore
   const subject = simpleIcons[variableName];
 
   testIcon(icon, subject, slug);
diff --git a/tests/min-reporter.cjs b/tests/min-reporter.cjs
index 11f841097..a54a57908 100644
--- a/tests/min-reporter.cjs
+++ b/tests/min-reporter.cjs
@@ -1,8 +1,18 @@
+/**
+ * @file Custom mocha reporter.
+ *
+ * Serves to clear the console after the test run is finished.
+ * See {@link https://github.com/mochajs/mocha/issues/2312}
+ */
+
 const {reporters, Runner} = require('mocha');
 
 const {EVENT_RUN_END} = Runner.constants;
 
 class EvenMoreMin extends reporters.Base {
+  /**
+   * @param {import('mocha').Runner} runner Mocha test runner
+   */
   constructor(runner) {
     super(runner);
     runner.once(EVENT_RUN_END, () => this.epilogue());
diff --git a/tests/test-icon.js b/tests/test-icon.js
index 409e13812..c9fe8f04b 100644
--- a/tests/test-icon.js
+++ b/tests/test-icon.js
@@ -1,3 +1,7 @@
+/**
+ * @file Icon tester.
+ */
+
 import {strict as assert} from 'node:assert';
 import fs from 'node:fs/promises';
 import path from 'node:path';
@@ -14,15 +18,11 @@ const iconsDirectory = path.resolve(
   'icons',
 );
 
-/**
- * @typedef {import('..').SimpleIcon} SimpleIcon
- */
-
 /**
  * Checks if icon data matches a subject icon.
- * @param {SimpleIcon} icon Icon data
- * @param {SimpleIcon} subject Icon to check against icon data
- * @param {String} slug Icon data slug
+ * @param {import('../sdk.d.ts').IconData} icon Icon data
+ * @param {import('../types.d.ts').SimpleIcon} subject Icon object to check against icon data
+ * @param {string} slug Icon data slug
  */
 export const testIcon = (icon, subject, slug) => {
   const svgPath = path.resolve(iconsDirectory, `${slug}.svg`);
@@ -62,8 +62,10 @@ export const testIcon = (icon, subject, slug) => {
 
     it(`has ${icon.license ? 'the correct' : 'no'} "license"`, () => {
       if (icon.license) {
-        assert.equal(subject.license.type, icon.license.type);
+        assert.equal(subject.license?.type, icon.license.type);
         if (icon.license.type === 'custom') {
+          // TODO: `Omit` not working smoothly here
+          // @ts-ignore
           assert.equal(subject.license.url, icon.license.url);
         }
       } else {
diff --git a/types.d.ts b/types.d.ts
index ab2ea35ac..202425a11 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -1,6 +1,9 @@
+/**
+ * @file Types for Simple Icons package.
+ */
+
 /**
  * The license for a Simple Icon.
- *
  * @see {@link https://github.com/simple-icons/simple-icons/blob/develop/CONTRIBUTING.md#optional-data Optional Data}
  */
 export type License = SPDXLicense | CustomLicense;