$ git clone -n https://src.fedoraproject.org/rpms/rubygem-scrub_rb.git /var/lib/mock/f45-build-35284-694/root/chroot_tmpdir/scmroot/rubygem-scrub_rb
Cloning into '/var/lib/mock/f45-build-35284-694/root/chroot_tmpdir/scmroot/rubygem-scrub_rb'...
$ git fetch origin 90e6f15c16350e8bdade5b20472d3daa972b3c2a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-scrub_rb
 * [new ref]         90e6f15c16350e8bdade5b20472d3daa972b3c2a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 90e6f15 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild