$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-Polygon.git /var/lib/mock/f45-build-24718-605/root/chroot_tmpdir/scmroot/perl-Math-Polygon
Cloning into '/var/lib/mock/f45-build-24718-605/root/chroot_tmpdir/scmroot/perl-Math-Polygon'...
$ git fetch origin ad8309cb36a535d4b61b897733142dfeb67ea846:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-Polygon
 * [new ref]         ad8309cb36a535d4b61b897733142dfeb67ea846 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ad8309c Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild