They come with kLIBC usually though some on HPFS can come from Linux.
Originally some of these such as the UID were implemented as part of the Linux R/W HPFS driver to support Linux permissions, same with symlink support. They were then ported to OS/2 as part of kLIBC and also extended to all file systems that support EAs. Knut also added more as he has plans and has been very resistant to removing them, but he hasn't seemed to have time to work on kLIBC for quite a while.
Note that the Linux driver only added these if you changed the defaults, ownership and/or permissions whereas kLIBC seems to add them to every file it touches.