Last modified: 2010-11-04 11:38:52 UTC
This was an artifact of a bad bit in the upgrade on en.wikipedia.org:
message updates were done when we had an incomplete page table, then the
page table was overwritten.
The revision entries created thus have bogus rev_page pointers and are
attached to seemingly random pages.
They should be easy to identify and remove -- 'MediaWiki default' edits
on non-MediaWiki: pages.
There were 622 such revisions, removed all of them.