Examine source code of Gmail Show Time

{
  "version": "3.7.1",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "{547cc27d-9dd7-4702-b918-ed993ac840d6}",
      "strict_min_version": "109.0"
    }
  },
  "name": "__MSG_appName__",
  "description": "__MSG_appDesc__",
  "default_locale": "en",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://mail.google.com/*"
      ],
      "run_at": "document_idle",
      "all_frames": false,
      "js": [
        "mutation-summary.min.js",
        "main.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "background": {
    "scripts": [
      "event.js"
    ]
  },
  "permissions": [
    "storage"
  ]
}