I'd guess that the issue is running the `%install` and `%check` stages of the .spec file. The Python library rpy (to pull a random example from Marcin's PRs) runs rpy's pytest test suite and had to be modified to avoid running vector tests on RISC-V.

Obviously a solvable problem to split build and test but perhaps the time savings aren't worth the complexity.

https://src.fedoraproject.org/rpms/rpy/pull-request/4#reques...

Near as I know, Fedora prefers native compilation for the builds.

Your question made me look up Arm's history in Fedora and came up on this 2012 LWN thread[1]. There's some discussion against cross-compilation already back then.

[1] https://lwn.net/Articles/487622/

It's usually an enormous pain to set up. QEMU is probably the best option.