$ git clone -n https://src.fedoraproject.org/rpms/rpkg-macros.git /var/lib/mock/f39-build-1895834-42814/root/chroot_tmpdir/scmroot/rpkg-macros
Cloning into '/var/lib/mock/f39-build-1895834-42814/root/chroot_tmpdir/scmroot/rpkg-macros'...
$ git fetch origin a1e98bf6f6267643091ce7a3725f312f506eddbc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rpkg-macros
 * [new ref]         a1e98bf6f6267643091ce7a3725f312f506eddbc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a1e98bf Fix FTBFS caused by testsuite in F38+