Examine source code of Things Quick Entry

{
  "manifest_version": 3,
  "name": "Things Quick Entry",
  "description": "Send the current tab to Things 3 for Mac with pre-filled title and URL.",
  "version": "1.0.0",
  "author": "Sridhar Katakam",
  "homepage_url": "https://github.com/srikat/things-quick-entry",
  "browser_specific_settings": {
    "gecko": {
      "id": "things-quick-entry@sridharkatakam.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "256": "images/things.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "options_ui": {
    "page": "options/options.html"
  },
  "action": {
    "default_icon": "images/things.png",
    "default_title": "Things Quick Entry"
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Alt+T",
        "mac": "MacCtrl+T"
      },
      "description": "Send current tab to Things"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}