WebKit version 1.1.1 released on 01/18/13
cgi.FieldStorage elements to the
  plain WebKit.request().fields() had a quadratic running time
  and could seriously slow down requests sending many different fields.
  This conversion is now done much faster and in linear time.filenamesForBaseName()
  method in the URLParser class. If the filename matches exactly,
  then we return only that filename.
  Earlier, if you had test.js
  and test.js.bak,
  and requested test.js,
  then you got a 404 "ambiguous filename" error.
  This is not really what you would expect in that situation.AutoReloadingAppServer.HTTPRequest.serverPath() did not work properly when
  SCRIPT_URL was not set by the webserver and the request had
  been forwarded (bug reported by Adam Smith).SessionDynamicStore
  when manipulating the sessions in a different thread.