Examine source code of ICS Import Create

{
  "manifest_version": 2,
  "name": "ICS Import Create",
  "version": "1.4.2",
  "description": "Add selected date/time text to your favorite calendar.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{0fba18a4-4086-4949-9c23-c360501bf014}",
      "strict_min_version": "104.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "contextMenus",
    "downloads",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js",
      "ics.js"
    ]
  },
  "icons": {
    "48": "icons/calendar.png",
    "256": "icons/calendar-logo.png"
  }
}