Well, they’re still available, but you don’t want them in your config any more because they can slow you down. This will only affect you if you are running binary files from DragonFly 1.2 or earlier, or… I guess a 4.3 BSD binary? From 1986? I’m sure there’s some other reason for it to be there.
Matthew Dillon wrote up an explanation of how performance on systems with a lot of CPU cores has been significantly improved – up to 300%! (He says 200%, but I think he’s treating it as a percentage of a whole rather than percent changed.) Apparently finally getting rid of lock contention is the trick.