Examine source code of Grmmr

{
  "manifest_version": 2,
  "name": "Grmmr",
  "version": "0.0.1",
  "description": "AI-powered grammar and writing assistant",
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ],
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "browser-polyfill.js",
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "web_accessible_resources": [
    "suggestion-card.html",
    "suggestion-card.css"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "grmmr@namang.me",
      "strict_min_version": "58.0"
    }
  }
}