Examine source code of Tab Limiter Extension

{
  "manifest_version": 2,
  "name": "Tab Limiter",
  "version": "1.1.0",
  "description": "Limits the number of tabs that can be open in a session",
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "./background.js"
    ]
  },
  "options_ui": {
    "page": "./options/options.html",
    "open_in_tab": false,
    "browser_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ad11c0bb-4fa5-4919-946e-b6e351863149}"
    }
  }
}