$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-BaseCnv.git /var/lib/mock/f45-build-24673-605/root/chroot_tmpdir/scmroot/perl-Math-BaseCnv
Cloning into '/var/lib/mock/f45-build-24673-605/root/chroot_tmpdir/scmroot/perl-Math-BaseCnv'...
$ git fetch origin 4b6afc1a371743dad1857e5a933c0c5a28f32bb5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-BaseCnv
 * [new ref]         4b6afc1a371743dad1857e5a933c0c5a28f32bb5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4b6afc1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild