Examine source code of Grammar Checker

{
  "manifest_version": 2,
  "name": "Grammar Checker",
  "version": "1.0",
  "description": "Check grammar in selected text using an external grammar API.",
  "permissions": [
    "contextMenus",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Grammar Checker"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{41836edb-3fb6-482f-96d6-a817ed421693}"
    }
  }
}