Examine source code of Highlight Selection

{
  "manifest_version": 3,
  "name": "Highlight Selection",
  "version": "1.0",
  "description": "Highlights currently selected text with a yellow background.",
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_title": "Highlight",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icons/icon.svg"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ext-highlight-selection@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [],
        "description": "This extension does not collect or transmit user data."
      }
    }
  }
}