Examine source code of External Application Button (WebExtension)

{
  "manifest_version": 3,
  "version": "0.6.0",
  "name": "External Application Launcher",
  "description": "Run any external application with custom arguments from the browser toolbar or context menu to send links, text and more",
  "permissions": [
    "activeTab",
    "storage",
    "contextMenus",
    "nativeMessaging",
    "downloads",
    "notifications",
    "declarativeNetRequestWithHostAccess",
    "scripting"
  ],
  "optional_permissions": [
    "tabs"
  ],
  "optional_host_permissions": [
    "*://*/*"
  ],
  "homepage_url": "https://webextension.org/listing/external-application-button.html",
  "background": {
    "service_worker": "worker.js",
    "scripts": [
      "termlib_parser.js",
      "navigation.js",
      "triggers/core.js",
      "worker.js"
    ]
  },
  "offline_enabled": true,
  "options_ui": {
    "page": "/data/options/index.html",
    "open_in_tab": true
  },
  "action": {},
  "icons": {
    "16": "/data/icons/16.png",
    "32": "/data/icons/32.png",
    "48": "/data/icons/48.png",
    "64": "/data/icons/64.png",
    "128": "/data/icons/128.png",
    "256": "/data/icons/256.png",
    "512": "/data/icons/512.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "/data/redirect/index.html"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "commands": {
    "_execute_action": {},
    "shortcut-1": {
      "description": "Custom Shortcut (1)"
    },
    "shortcut-2": {
      "description": "Custom Shortcut (2)"
    },
    "shortcut-3": {
      "description": "Custom Shortcut (3)"
    },
    "shortcut-4": {
      "description": "Custom Shortcut (4)"
    },
    "shortcut-5": {
      "description": "Custom Shortcut (5)"
    },
    "shortcut-6": {
      "description": "Custom Shortcut (6)"
    },
    "shortcut-7": {
      "description": "Custom Shortcut (7)"
    },
    "shortcut-8": {
      "description": "Custom Shortcut (8)"
    },
    "shortcut-9": {
      "description": "Custom Shortcut (9)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{65b77238-bb05-470a-a445-ec0efe1d66c4}",
      "strict_min_version": "128.0"
    }
  }
}