Hi @james-traxler_1560,
I'm not really sure I totally understand the issue, or how to resolve it... but I'll explain how a GET manifest request to your URL would work.
Basically, ProGet returns whatever manifest file you uploaded, or whatever was downloaded via the connector. We do not generate the manifest files, or pay attention to the Accept request header.
I understand that application/vnd.docker.distribution.manifest.list.v2+json is a "fat manifest", which is basically a manifest that points to other manifests on different architectures. So you don't know exactly what image you'll get until you install it on the machine.
So if you want to inspect layers, you would first need to decide which manifest to use, I guess
Cheers,
Alana