$ git clone -n https://src.fedoraproject.org/rpms/kscreenlocker.git /var/lib/mock/f42-build-side-1-3575208-46778/root/chroot_tmpdir/scmroot/kscreenlocker
Cloning into '/var/lib/mock/f42-build-side-1-3575208-46778/root/chroot_tmpdir/scmroot/kscreenlocker'...
$ git fetch origin be8fbdb977a1ae279c4e050474f53a531aaf97dd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kscreenlocker
 * [new ref]         be8fbdb977a1ae279c4e050474f53a531aaf97dd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be8fbdb 6.4.0