Examine source code of Fontanello

{
  "name": "Fontanello",
  "version": "1.4.0",
  "description": "A browser extension that lets you display the basic typographic styles of a text by right-clicking it.",
  "background": {
    "service_worker": "background.js",
    "type": "module",
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "optional_permissions": [
    "offscreen",
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "client.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "minimum_chrome_version": "109",
  "manifest_version": 3,
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{768bd125-21c9-41b7-9bed-ffce6c787f36}"
    }
  }
}