Examine source code of Play with MPV

{
  "name": "Play with MPV",
  "version": "0.1.2",
  "manifest_version": 2,
  "description": "Sends videos in pages like youtube to an external MPV player",
  "homepage_url": "https://github.com/alesar1/play-with-mpv",
  "icons": {
    "114": "mpv-logo.png"
  },
  "page_action": {
    "default_icon": "mpv-logo.png",
    "default_title": "Play with MPV"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "storage",
    "activeTab",
    "contextMenus",
    "http://localhost/"
  ],
  "commands": {
    "launch": {
      "suggested_key": {
        "default": "Ctrl+Space"
      },
      "description": "Play with MPV"
    }
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fdcee1ba-e500-4f75-8645-fecaca75133b}"
    }
  }
}