Examine source code of track-a-lang

{
  "manifest_version": 2,
  "name": "track-a-lang",
  "description": "track comprehensible input time for any language",
  "version": "0.0.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "scripting"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "track-a-lang@quirkyquokka",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_title": "Default Popup Title",
    "default_popup": "popup.html"
  }
}