Examine source code of Tab Numbers ⚡

{
  "manifest_version": 2,
  "name": "Tab Numbers ⚡",
  "version": "1.0",
  "description": "Always shows the correct tab number in the tab title.",
  "permissions": [
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "icons": {
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tabnumbers@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "opt_in": false
      }
    }
  }
}