Examine source code of Creative Writing Coach

{
  "manifest_version": 2,
  "name": "Creative Writing Coach",
  "version": "3.0",
  "description": "Real-time writing feedback for Google Docs.",
  "permissions": [
    "https://docs.google.com/*",
    "tabs",
    "storage",
    "identity",
    "activeTab",
    "scripting"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "firefox-ext-writing-buddy@buddysuite.com"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}