$ git clone -n https://src.fedoraproject.org/rpms/python-nbxmpp.git /var/lib/mock/f45-build-31684-654/root/chroot_tmpdir/scmroot/python-nbxmpp
Cloning into '/var/lib/mock/f45-build-31684-654/root/chroot_tmpdir/scmroot/python-nbxmpp'...
$ git fetch origin f4d448b64128c6dae5c4f0edb37e7e69898aa8ce:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-nbxmpp
 * [new ref]         f4d448b64128c6dae5c4f0edb37e7e69898aa8ce -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f4d448b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild