Prebuilt blobs for build-time deps?

Well, on Flathub it is an requirement to build the software from source, whenever possible:

docs.flathub.org

Building from source​ - Requirements | Flathub Documentation

The goal of these requirements is to ensure that the applications hosted on Flathub are safe to use and integrate well in the desktop experience. | The goal of these requirements is to ensure that the applications hosted