$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-Symbolic.git /var/lib/mock/f45-build-24873-606/root/chroot_tmpdir/scmroot/perl-Math-Symbolic
Cloning into '/var/lib/mock/f45-build-24873-606/root/chroot_tmpdir/scmroot/perl-Math-Symbolic'...
$ git fetch origin 88b37b2074a1c5b55e12101d6a5b8425d4d971fd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-Symbolic
 * [new ref]         88b37b2074a1c5b55e12101d6a5b8425d4d971fd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 88b37b2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild