$ git clone -n https://src.fedoraproject.org/rpms/meanwhile.git /var/lib/mock/f45-build-18193-511/root/chroot_tmpdir/scmroot/meanwhile
Cloning into '/var/lib/mock/f45-build-18193-511/root/chroot_tmpdir/scmroot/meanwhile'...
$ git fetch origin 51e84ab8c8738c722c73dfda87ac6a0ddeff3a72:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/meanwhile
 * [new ref]         51e84ab8c8738c722c73dfda87ac6a0ddeff3a72 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51e84ab Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild