What happened to /usr/local? What are these /usr/contrib

What happened to /usr/local? What are these /usr/contrib and /opt directories?

Updated: 04/04/01

As of HP-UX 10.00, things have been moved around some -- probably for
the better:

optional HP software packages like the ANSI C & C++ compilers and
debuggers, and the Java[TM] SDK; larger 3rd-party apps (ie - emacs,
Perl 5)
Unsupported, 3rd-party or public-domain software compiled and
maintained by the local IT group on their software depot
(ie - nn, gzip & other GNU utils)
workstation-unique software packages that users have installed
themselves, or are local to a specific machine. This directory
is world-writable (ack!).

For more information on the SVR4 filesystem layout, see hier(5).