The Common Desktop Environment (CDE) was the dominant desktop on
proprietary Unix systems in the 90's. In 2012 it was relicensed under
GPL2 and has seen moderst maintenance from the community. Although
functional, it is of course a very old desktop, and some parts of it,
such as the calendar and mail applications, are not likely useful in a
modern setting. (NsCDE is a good alternative if you want a modern CDE
look-a-like) Nevertheless, people still use it today, for nostalgia, if
nothing else.

PS: The RPC service needs to be running for CDE to work:

# chmod +x /etc/rc.d/rc.rpc
# /etc/rc.d/rc.rpc start

PPS: gawk is symlinked to nawk, since CDE "needs" nawk to work.