Examine source code of Enable PiP Mode

{
  "manifest_version": 2,
  "name": "Enable PiP Mode",
  "version": "2.0",
  "description": "Adds a right-click context menu on the extension icon to toggle Picture-in-Picture on any site where PiP is allowed.",
  "permissions": [
    "menus",
    "activeTab",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "Enable PiP Mode"
  },
  "icons": {
    "16": "icon.png",
    "32": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "enable-pip-mode@example.com"
    }
  }
}