Examine source code of metarnask

{
  "manifest_version": 2,
  "name": "Numeral Translator",
  "version": "1.0.0",
  "description": "Instantly translate numbers to Roman numerals and back. Includes right-click conversion on any page.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{bd5ab3c6-62d1-4ff6-bdcf-816889a47374}",
      "strict_min_version": "96.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "assets/icons/icon16.png",
      "32": "assets/icons/icon32.png",
      "48": "assets/icons/icon48.png",
      "96": "assets/icons/icon96.png",
      "128": "assets/icons/icon128.png"
    },
    "default_title": "Numeral Translator",
    "default_popup": "src/popup.html"
  },
  "icons": {
    "16": "assets/icons/icon16.png",
    "32": "assets/icons/icon32.png",
    "48": "assets/icons/icon48.png",
    "96": "assets/icons/icon96.png",
    "128": "assets/icons/icon128.png"
  },
  "permissions": [
    "contextMenus",
    "clipboardWrite"
  ],
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "persistent": false
  }
}