$ git clone -n https://src.fedoraproject.org/rpms/Perlbal.git /var/lib/mock/f41-build-816639-150311/root/chroot_tmpdir/scmroot/Perlbal
Cloning into '/var/lib/mock/f41-build-816639-150311/root/chroot_tmpdir/scmroot/Perlbal'...
$ git fetch origin 6a36954bea8139fdbb9d11e26695de2d9d16523a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/Perlbal
 * [new ref]         6a36954bea8139fdbb9d11e26695de2d9d16523a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6a36954 Perl 5.40 rebuild