Examine source code of music-bridge

{
  "manifest_version": 2,
  "name": "__MSG_name__",
  "description": "__MSG_description__",
  "version": "1.5.4",
  "icons": {
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "default_locale": "en",
  "content_scripts": [
    {
      "matches": [
        "https://open.spotify.com/*/track/*",
        "https://open.spotify.com/*/album/*",
        "https://www.deezer.com/*/track/*",
        "https://www.deezer.com/*/album/*",
        "https://music.apple.com/*/album/*",
        "https://beta.music.apple.com/*/album/*",
        "https://music.youtube.com/watch?v=*",
        "https://music.youtube.com/playlist?list=*",
        "https://listen.tidal.com/track/*",
        "https://listen.tidal.com/album/*",
        "https://www.pandora.com/TR:*",
        "https://www.pandora.com/AL:*",
        "https://music.amazon.com/albums/*",
        "https://web.napster.com/track/*",
        "https://web.napster.com/album/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{987b3f6c-05ca-4dc6-a140-38ce920051c7}"
    }
  }
}