When I click on the TUAW feed in Newsblur in Safari (5.1.2 (7534.52.7)) it downloads a file named PkV3_AWFpVY. Not every time I click on it but when I first open Newsblur or when I leave it open in a tab and then come back after a time, as soon as I click on TUAW’s feed the file downloads.
I can’t remember this happening to any other feed but I can’t be sure.