$ git clone -n https://src.fedoraproject.org/rpms/perl-Image-Math-Constrain.git /var/lib/mock/f41-build-780060-13558/root/chroot_tmpdir/scmroot/perl-Image-Math-Constrain
Cloning into '/var/lib/mock/f41-build-780060-13558/root/chroot_tmpdir/scmroot/perl-Image-Math-Constrain'...
$ git fetch origin 674bdeeb489fa569215b998510f08541792cee08:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Image-Math-Constrain
 * [new ref]         674bdeeb489fa569215b998510f08541792cee08 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 674bdee Eliminate use of obsolete %patchN syntax (#2283636)