$ git clone -n https://src.fedoraproject.org/rpms/frozen-bubble.git /var/lib/mock/f41-build-816811-150442/root/chroot_tmpdir/scmroot/frozen-bubble
Cloning into '/var/lib/mock/f41-build-816811-150442/root/chroot_tmpdir/scmroot/frozen-bubble'...
$ git fetch origin 8e384afe6a90633214bd7c4490ce294ae80d9cc2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/frozen-bubble
 * [new ref]         8e384afe6a90633214bd7c4490ce294ae80d9cc2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8e384af Perl 5.40 rebuild