This is https://github.com/rpm-software-management/rpm/issues/3147, but when using rpmbuild through fedpkg.

On rawhide, I want to find the directory where a package was built. For the last few years, I had assumed a hardcoded path. That path was recently changed in rpm. rpm is now working on a way to expose this information via https://github.com/rpm-software-management/rpm/issues/3147.

They have a workaround described on that issue:

rpmbuild -bc --short-circuit --define '__spec_build_pre echo builddir=%{_builddir}; exit 0' foo.spec |awk /^builddir/

However, this workaround doesn't produce the same location as when doing a fedpgk local.

fedpgk calls rpmbuild with several additional flags (including _builddir). I don't know of a clean way to extract the rpmbuild command fedpkg would have used (without running it again) and combine it with rpmbuild to get the directory where a package was built.