Examine source code of Mark My Tab

{
  "manifest_version": 2,
  "name": "Mark My Tab",
  "version": "1.1",
  "description": "Marks tabs with a badge of a predefined color",
  "homepage_url": "https://github.com/maslisko/mark-my-tab",
  "icons": {
    "16": "icons/mark-my-tab-icon16.png",
    "48": "icons/mark-my-tab-icon48.png",
    "64": "icons/mark-my-tab-icon64.png",
    "128": "icons/mark-my-tab-icon128.png"
  },
  "permissions": [
    "<all_urls>",
    "activeTab",
    "menus",
    "contextMenus",
    "tabs"
  ],
  "background": {
    "scripts": [
      "badger.js",
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "mark-my-tab@maslisko",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}