Examine source code of Grammarly Lite

{
  "manifest_version": 2,
  "name": "Grammarly Lite",
  "version": "1.2",
  "description": "A simple grammar and spell checker.",
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8c4464ed-4398-42c1-bf11-0ccb81967d16}"
    }
  }
}