$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-GMP.git /var/lib/mock/f45-build-24679-605/root/chroot_tmpdir/scmroot/perl-Math-GMP
Cloning into '/var/lib/mock/f45-build-24679-605/root/chroot_tmpdir/scmroot/perl-Math-GMP'...
$ git fetch origin 70f385a06523d7341a5239fa160967c4c0ddf891:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-GMP
 * [new ref]         70f385a06523d7341a5239fa160967c4c0ddf891 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 70f385a Perl 5.44 rebuild