Examine source code of Mail Scout

{
  "name": "Mail Scout",
  "version": "1.1.0",
  "manifest_version": 2,
  "permissions": [
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.bundle.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.bundle.js"
      ],
      "run_at": "document_end"
    }
  ],
  "sidebar_action": {
    "default_panel": "panel.html"
  },
  "browser_action": {
    "default_title": "Mail Scout",
    "default_icon": {
      "16": "/assets/icon_nobg_128.png",
      "32": "/assets/icon_nobg_128.png",
      "64": "/assets/icon_nobg_128.png",
      "128": "/assets/icon_nobg_128.png"
    }
  },
  "icons": {
    "16": "/assets/icon_nobg_128.png",
    "32": "/assets/icon_nobg_128.png",
    "64": "/assets/icon_nobg_128.png",
    "128": "/assets/icon_nobg_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{75756ae2-bb4a-4459-82e4-0bae0383ec58}"
    }
  }
}