$ git clone -n https://src.fedoraproject.org/rpms/kscreenlocker.git /var/lib/mock/f40-build-2087279-50154/root/chroot_tmpdir/scmroot/kscreenlocker
Cloning into '/var/lib/mock/f40-build-2087279-50154/root/chroot_tmpdir/scmroot/kscreenlocker'...
$ git fetch origin bceb65eb1f9f5d75e2a1fda6d53beb412ec8931e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kscreenlocker
 * [new ref]         bceb65eb1f9f5d75e2a1fda6d53beb412ec8931e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bceb65e fix: upload missing sources