$ git clone -n https://src.fedoraproject.org/rpms/hexglass.git /var/lib/mock/f41-build-1021588-18027/root/chroot_tmpdir/scmroot/hexglass
Cloning into '/var/lib/mock/f41-build-1021588-18027/root/chroot_tmpdir/scmroot/hexglass'...
$ git fetch origin 9929cd073d774e96b8b258d012e90f52ac11e50e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/hexglass
 * [new ref]         9929cd073d774e96b8b258d012e90f52ac11e50e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9929cd0 Eliminate use of obsolete %patchN syntax (#2283636)