This is the MPLS label value this router expects to see on packets arriving from the peer for this pseudowire, i.e. the label the far end must use when sending traffic toward this router, with -1 presumably indicating no label has been allocated yet (e.g., the PW is down or unsignaled). This is a core piece of low-level pseudowire troubleshooting data: if this shows -1 while the PW is expected to be up, it directly indicates the local LDP session has not successfully allocated an inbound label for this PW. A value like 24576 would tell an engineer exactly which label to look for when capturing or tracing MPLS traffic destined for this pseudowire on this router.