Examine source code of CalendarThat

{
  "name": "CalendarThat",
  "version": "1.1",
  "manifest_version": 3,
  "description": "Right-click to send highlighted text to CalendarThat.",
  "permissions": [
    "contextMenus",
    "storage",
    "scripting",
    "downloads",
    "activeTab"
  ],
  "host_permissions": [
    "https://calendarthat.com/*"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/logged_in_16.png",
      "32": "icons/logged_in_32.png",
      "48": "icons/logged_in_48.png",
      "128": "icons/logged_in_128.png"
    }
  },
  "background": {
    "scripts": [
      "background_listeners.js"
    ],
    "type": "module"
  },
  "icons": {
    "16": "icons/logged_in_16.png",
    "32": "icons/logged_in_32.png",
    "48": "icons/logged_in_48.png",
    "128": "icons/logged_in_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "calendarthat.extension@calendarthat.com"
    }
  }
}