Examine source code of Xdebug-ext+

{
  "description": "Adds a simple button to inject a Xdebug cookie.",
  "manifest_version": 2,
  "name": "Xdebug-ext+",
  "version": "1.1",
  "homepage_url": "https://github.com/JakubJachym/xdebug-ext-plus",
  "icons": {
    "48": "data/icons/debug_48_active.png"
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "data/icons/debug_32_inactive.png",
    "default_title": "Xdebug"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{22828ac9-fe43-4139-bdbb-7fc43ddd6602}"
    }
  }
}