$ git clone -n https://src.fedoraproject.org/rpms/perl-Crypt-DH-GMP.git /var/lib/mock/f43-perl-60958945-6586769/root/chroot_tmpdir/scmroot/perl-Crypt-DH-GMP
Cloning into '/var/lib/mock/f43-perl-60958945-6586769/root/chroot_tmpdir/scmroot/perl-Crypt-DH-GMP'...
$ git fetch origin 9763c59a103d23ffda60f4655ce1265f54780acb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Crypt-DH-GMP
 * [new ref]         9763c59a103d23ffda60f4655ce1265f54780acb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9763c59 Perl 5.42 rebuild