$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-Random-MT.git /var/lib/mock/f45-build-24687-605/root/chroot_tmpdir/scmroot/perl-Math-Random-MT
Cloning into '/var/lib/mock/f45-build-24687-605/root/chroot_tmpdir/scmroot/perl-Math-Random-MT'...
$ git fetch origin 3d0e26b90de3c925cb7358a264d2bd15e62286e9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-Random-MT
 * [new ref]         3d0e26b90de3c925cb7358a264d2bd15e62286e9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d0e26b Perl 5.44 rebuild