$ git clone -n https://src.fedoraproject.org/rpms/perl-Cache-FastMmap.git /var/lib/mock/f45-build-22102-589/root/chroot_tmpdir/scmroot/perl-Cache-FastMmap
Cloning into '/var/lib/mock/f45-build-22102-589/root/chroot_tmpdir/scmroot/perl-Cache-FastMmap'...
$ git fetch origin 926613a8c6a83187ebd3ff06abd1d291ab09c7aa:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Cache-FastMmap
 * [new ref]         926613a8c6a83187ebd3ff06abd1d291ab09c7aa -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 926613a 1.63 bump (rhbz#2515967)