To venture a guess, "eu_aspect='S'" seems to be the page-to-item identity, with the exception of redirected items, which still appear to be associated with the page (e.g. page_id 8983308 on dewiki).

On Tue, Mar 29, 2016 at 12:10 AM Magnus Manske <magnusmanske@googlemail.com> wrote:

I'm sure this is documented somewhere, but...

In the Labs DB replicas, I see the wbc_entity_usage table. I assume that logs the Wikidata entities used for a particlar page.

* What is eu_aspect? What do "L.de"/O/S/T/X mean?
* Is one of these the item ID of the page (as opposed to "arbitary use")? If so, which one? If not, how could I find this information on the replicas?