Last modified: 2009-06-18 09:02:10 UTC
The "new" flag on usercontribs API results is supposed to indicate that the edit created a new page. And so it does on more recent contributions, but only back to mid April 2008. All edits made before then are flagged as new. e.g. see <http://en.wikipedia.org/w/api.php?action=query&list=usercontribs&ucuser=Jimbo_Wales&&ucdir=newer&ucstart=2008-04-01T00:00:00Z>
Fixed in r52096. All pre-April 2008 revisions will now be incorrectly reported as *not* new, which is of course still incorrect, but much less confusing. Getting the new flag to work correctly for these old revisions requires the rev_parent_id population script to be run on WMF wikis; I think there might be an open bug for that even.