$ git clone -n https://src.fedoraproject.org/rpms/rubygem-flexmock.git /var/lib/mock/f45-build-34925-692/root/chroot_tmpdir/scmroot/rubygem-flexmock
Cloning into '/var/lib/mock/f45-build-34925-692/root/chroot_tmpdir/scmroot/rubygem-flexmock'...
$ git fetch origin 6e954eb785d4c65643375f3529b497a7d0a398e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-flexmock
 * [new ref]         6e954eb785d4c65643375f3529b497a7d0a398e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6e954eb Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild