Examine source code of GCL Extension

{
  "name": "GCL Extension",
  "version": "0.4",
  "manifest_version": 2,
  "description": "Remplace des noms de politocards sur toutes les pages internet",
  "browser_action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    },
    "default_popup": "options/options.html"
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{521ec28d-30cd-4431-af4d-cecaf5170292}"
    }
  }
}