Undocumented devices?

[Anthony A. Datri]

I'm pokin' around in /usr/sys building kernels with Valid's license stuff.
Sigh.  But I find some interesting things, at least on a 3x, in files.c:

sunif/if_hy.c           optional hy not-supported
   Have they been working on a hyperchannel link?
sundev/pi.c             optional pi not-supported
sundev/ropc.c           optional ropc not-supported
sundev/kg.c             optional kg device-driver
sundev/ft.c             optional ft device-driver
sundev/hrc.c            optional hrc device-driver
sundev/hrc_kern.c       optional hrc device-driver
sundev/pc.c             optional pc device-driver
sundev/pc_conf.c        optional pc device-driver
sundev/se.c             optional se device-driver
sundev/sf.c             optional sf device-driver
sunif/tbi.c             optional tbi device-driver

There are also in thed OBJ directory:
atalk.h
chat.h
ifd.h
sqzd.h

Any idea what the rest of these are?  I'm not a kernel guru, but these
smack of drivers under development / abandoned drivers to me.  Of course,
it's also possible that these have some normal usage that I can't see.