could also forgo the umbraco-pacakge.json for... (Awesom Kevin/Søren) added bonus of automatic/centralised versioning....

csharp
using System.Reflection;
using Umbraco.Cms.Core.Manifest;

namespace Lovell.Code.Extensions
{
    public class InvisiblePackageManifestReader : IPackageManifestReader
    {
        public Task<IEnumerable<PackageManifest>> ReadPackageManifestsAsync()
        {
            // Dynamically grab your real assembly version
            var assemblyVersion = Assembly.GetExecutingAssembly()
                .GetName().Version?.ToString(3) ?? "1.0.0";

            var ghostManifest = new PackageManifest
            {
                Id = "", // Matches your package ID
                Name = "",
                Version = assemblyVersion,
                Extensions = Array.Empty<object>() // The magic line: empty array forces it into the list without loading frontend assets
            };

            return Task.FromResult<IEnumerable<PackageManifest>>(new[] { ghostManifest });
        }
    }
}