$ git clone -n https://src.fedoraproject.org/rpms/rubygem-mixlib-log.git /var/lib/mock/f45-build-35100-693/root/chroot_tmpdir/scmroot/rubygem-mixlib-log
Cloning into '/var/lib/mock/f45-build-35100-693/root/chroot_tmpdir/scmroot/rubygem-mixlib-log'...
$ git fetch origin 8bf53b624961b684b8ec791e50de98722cb110a0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-mixlib-log
 * [new ref]         8bf53b624961b684b8ec791e50de98722cb110a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8bf53b6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild