The Satellite flatpak registry is not a complete flatpak index registry. It is a prxy between client -> pulp which intercepts and forwards requests between the two. The main goal of this registry proxy in Satellite is to enforce lifecycle restrictions.

When we get the flatpak index from pulp, that contains all the flatpak images known to pulp. Satellite needs to filter this list to only return images that the client has access to via it's registered CV-LCE..