Examine source code of Grammar Checker and Writing Assistant by Sapling

{
  "manifest_version": 3,
  "name": "Sapling Grammar Checker and Writing Assistant",
  "short_name": "Sapling",
  "description": "AI-powered grammar checking, paraphrase, and autocomplete for email, docs, chat, and more.",
  "version": "3.2.4.6",
  "author": "sapling.ai",
  "icons": {
    "32": "assets/sapling-32x32.png",
    "48": "assets/sapling-48x48.png",
    "128": "assets/sapling-128x128.png",
    "176": "assets/sapling-176x176.png"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  },
  "action": {
    "default_icon": {
      "40": "assets/sapling-40x40.png"
    },
    "default_title": "Sapling",
    "default_popup": "generated/popup.html#saplingpopup"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "addon@sapling.ai",
      "strict_min_version": "128.0"
    }
  },
  "permissions": [
    "activeTab",
    "alarms",
    "clipboardRead",
    "clipboardWrite",
    "identity",
    "identity.email",
    "offscreen",
    "scripting",
    "storage",
    "tabs",
    "webNavigation"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "generated/jquery-3.5.1.min.js",
      "generated/background-bundle.js",
      "generated/clipboard-bundle.js"
    ]
  },
  "commands": {
    "accept-all-edits": {
      "suggested_key": {
        "default": "Alt+O",
        "mac": "MacCtrl+O"
      },
      "description": "Accept all edit suggestions"
    },
    "accept-current-sentence-edits": {
      "suggested_key": {
        "default": "Alt+I",
        "mac": "MacCtrl+I"
      },
      "description": "Accept edit suggestions in current sentence"
    },
    "toggle-snippet-controls": {
      "suggested_key": {
        "default": "Alt+L",
        "mac": "MacCtrl+L"
      },
      "description": "Launch snippet selector"
    },
    "toggle-rephrase-controls": {
      "description": "Launch rephrase popup",
      "suggested_key": {
        "default": "Ctrl+J",
        "mac": "Command+J"
      }
    },
    "_execute_action": {}
  },
  "content_scripts": [
    {
      "matches": [
        "https://sapling.ai/main_declarative_injection_dont_remove",
        "https://*.workplaceoptions.com/*",
        "http://localhost:8000/*",
        "http://localhost:3176/*"
      ],
      "js": [
        "generated/jquery-3.5.1.min.js",
        "generated/main-bundle.js"
      ],
      "all_frames": true,
      "match_about_blank": true
    },
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "js": [
        "scripts/gmail-injector.js"
      ],
      "run_at": "document_start"
    }
  ],
  "externally_connectable": {
    "matches": [
      "https://mail.google.com/*"
    ]
  },
  "web_accessible_resources": [
    {
      "resources": [
        "assets/*",
        "generated/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    },
    {
      "resources": [
        "generated/gmail-module.js",
        "generated/gmail-listener.js"
      ],
      "matches": [
        "*://mail.google.com/*"
      ]
    }
  ]
}