$ git clone -n https://src.fedoraproject.org/rpms/perl-IO-Multiplex.git /var/lib/mock/f45-build-24162-602/root/chroot_tmpdir/scmroot/perl-IO-Multiplex
Cloning into '/var/lib/mock/f45-build-24162-602/root/chroot_tmpdir/scmroot/perl-IO-Multiplex'...
$ git fetch origin 1516ca46832ef48e6d1dfadc5e06e1756ebd3199:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-IO-Multiplex
 * [new ref]         1516ca46832ef48e6d1dfadc5e06e1756ebd3199 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1516ca4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild