Examine source code of Grammate Helper

{
  "manifest_version": 2,
  "name": "Grammate Helper",
  "version": "1.1",
  "description": "Silent browser helper for Grammate textbox and selection detection.",
  "permissions": [
    "storage",
    "tabs",
    "<all_urls>",
    "http://127.0.0.1/*",
    "http://localhost/*"
  ],
  "options_page": "site-access.html",
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "background": {
    "scripts": [
      "content-script-core-foundation.js",
      "content-script-core-replacement.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "content-script-page-bridge.js"
      ],
      "match_about_blank": true,
      "match_origin_as_fallback": true,
      "run_at": "document_start",
      "world": "MAIN"
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "content-script-core-foundation.js",
        "content-script-core-replacement.js",
        "content-script-main-viewport.js",
        "content-script-main-google-docs.js",
        "content-script-main.js"
      ],
      "match_about_blank": true,
      "match_origin_as_fallback": true,
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "grammate-helper@example.com",
      "data_collection_permissions": {
        "required": [
          "browsingActivity",
          "websiteContent",
          "websiteActivity"
        ]
      }
    }
  },
  "browser_action": {
    "default_popup": "site-access.html"
  }
}