#3 - Sept. 19, 2010, 6:12 a.m.
There are no new patch notes for this latest build as of yet, however, the Known Issues and Bug Fixes sections of the Cataclysm beta patch notes have many relevant listings:
http://forums.worldofwarcraft.com/thread.html?topicId=24702229998&sid=2000
The build being pushed to the public test realms is the same build pushed today to the beta test realms. The only difference is that the Cataclysm content is inaccessible on the 4.0.1 PTRs, so disregard any notes specific to Cataclysm found from that link.