$ git clone -n https://src.fedoraproject.org/rpms/libcoap.git /var/lib/mock/f39-build-1490031-34503/root/chroot_tmpdir/scmroot/libcoap
Cloning into '/var/lib/mock/f39-build-1490031-34503/root/chroot_tmpdir/scmroot/libcoap'...
$ git fetch origin af53b84ff4265ad88c78c160d64af32535976542:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libcoap
 * [new ref]         af53b84ff4265ad88c78c160d64af32535976542 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at af53b84 4.3.4