Examine source code of Translate Menu

{
  "manifest_version": 2,
  "name": "Translate Menu",
  "version": "0.4",
  "description": "Adds Translate to the context menu. Open Google Translate in a new tab and translate the page or selection text into your browser preferred language.",
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "57.0",
      "id": "{dac8a935-4775-4918-9205-5c0600087dc4}"
    }
  },
  "icons": {
    "48": "icon.svg"
  },
  "permissions": [
    "menus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  }
}