Examine source code of Listen.moe Player

{
  "author": "igorlogius",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_area": "navbar",
    "default_popup": "popup.html"
  },
  "commands": {
    "savePlaying": {
      "description": "Save Now Playing Info"
    },
    "showPlaying": {
      "description": "Display Now Playing Song Info"
    },
    "toggleFavorite": {
      "description": "Toggle Favorit Now Playing Song"
    },
    "togglePlayback": {
      "description": "Toggle Playback"
    },
    "toggleType": {
      "description": "Toggle RadioType"
    },
    "volDown": {
      "description": "Lower Volume"
    },
    "volUp": {
      "description": "Raise Volume"
    }
  },
  "description": "Listen to https://listen.moe",
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "name": "Listen.moe Player",
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "*://*.listen.moe/*",
    "storage",
    "notifications",
    "cookies"
  ],
  "version": "1.2.30",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9635e809-0990-44cf-9cdd-454749400c78}"
    }
  }
}