Examine source code of Audio Boost & Sync

{
  "manifest_version": 2,
  "name": "Audio Boost & Sync",
  "version": "1.0.0",
  "description": "Boost audio volume and adjust bass/treble automatically for web videos.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_title": "Audio Boost & Sync",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "audio-boost-sync@amo.local",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}