This read-only Integer32 is the 32-bit unsigned sum of the LS checksums of the link-state advertisements in this interface's link-local Link State Database, per its description, explicitly intended to let an engineer detect a change in that interface's link-local database and compare it against the corresponding database on other routers attached to the same subnet. Because link-local LSAs are only flooded to routers on that specific link, this checksum sum is the natural per-link consistency check rather than an area-wide or domain-wide one. An engineer suspecting two routers on the same shared subnet have inconsistent link-local data would compare this checksum sum on the matching interface of each router.