Examine source code of Active Tab Highlighter

{
  "manifest_version": 2,
  "name": "Active Tab Highlighter",
  "version": "1.1",
  "description": "Hebt den aktiven Tab hervor, ohne das Theme zu überschreiben.",
  "browser_specific_settings": {
    "gecko": {
      "id": "active-tab-highlighter@lof",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "collects_data": false
      }
    }
  },
  "permissions": [
    "tabs",
    "theme",
    "storage",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  }
}