Read the blog post: https://silvanhagen.com/writing/custom-driver-favicon-fetcher/

AppServiceProvider.php

<?php

namespace App\Providers;

use App\FaviconFetcher\Drivers\UnavatarServices;
use AshAllenDesign\FaviconFetcher\Facades\Favicon;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    public function register(): void
    {
        Favicon::extend('unavatar-services', new UnavatarServices());
    }
}