Examine source code of SaveTube

{
  "manifest_version": 2,
  "name": "SaveTube",
  "version": "2025.7.9",
  "description": "Download videos from video sharing web sites.",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "64": "icons/64.png",
    "96": "icons/96.png",
    "128": "icons/128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://youtube.com/*",
        "http://www.youtube.com/*",
        "https://youtube.com/*",
        "https://www.youtube.com/*",
        "http://m.youtube.com/*",
        "https://m.youtube.com/*",
        "http://dailymotion.com/*",
        "http://www.dailymotion.com/*",
        "https://dailymotion.com/*",
        "https://www.dailymotion.com/*",
        "http://vimeo.com/*",
        "http://www.vimeo.com/*",
        "https://vimeo.com/*",
        "https://www.vimeo.com/*",
        "http://veoh.com/*",
        "http://www.veoh.com/*",
        "https://veoh.com/*",
        "https://www.veoh.com/*",
        "http://imdb.com/*",
        "http://www.imdb.com/*",
        "https://imdb.com/*",
        "https://www.imdb.com/*"
      ],
      "js": [
        "savetube.user.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "http://manifest.googlevideo.com/*",
    "https://manifest.googlevideo.com/*",
    "http://player.vimeo.com/*",
    "https://player.vimeo.com/*",
    "http://api.vimeo.com/*",
    "https://api.vimeo.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{edb2cd6a-2bb4-4e75-bac6-aa41735c039f}"
    }
  }
}