$ git clone -n https://src.fedoraproject.org/rpms/samba.git /var/lib/mock/f45-build-46387-834/root/chroot_tmpdir/scmroot/samba
Cloning into '/var/lib/mock/f45-build-46387-834/root/chroot_tmpdir/scmroot/samba'...
$ git fetch origin d0c0d88885b9e41249bea36fd1eeb1134d25d9c2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/samba
 * [new ref]         d0c0d88885b9e41249bea36fd1eeb1134d25d9c2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d0c0d88 Update to Samba 4.25.0