Examine source code of Grammar Highlight

{
  "manifest_version": 2,
  "name": "Grammar Highlight",
  "version": "1.0",
  "description": "Highlight grammatical elements such as subjects, verbs, adverbs, etc.",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_title": "Grammar Highlight",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f0b3f3ba-0fbc-478d-9d9b-231fad352f8e}"
    }
  }
}