Examine source code of YouTube Embedify

{
  "manifest_version": 2,
  "name": "YouTube Embedify",
  "version": "4.0.0",
  "description": "Replaces YouTube video URLs with embed versions.",
  "permissions": [
    "tabs",
    "webNavigation",
    "storage",
    "theme",
    "*://www.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon.svg",
      "48": "icons/icon.svg",
      "128": "icons/icon.svg"
    },
    "default_popup": "src/popup.html"
  },
  "icons": {
    "16": "icons/icon.svg",
    "48": "icons/icon.svg",
    "128": "icons/icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3cead718-d015-4a4e-a931-746c63833433}"
    }
  }
}