Where are HTTP_SERVER_VARS?

Can anyone point me to a location in the source where I can find out
definitively what $HTTP_*_VARS are available and what are not.

With track_vars on I can see:

HTTP_GET_VARS
HTTP_POST_VARS
HTTP_COOKIE_VARS
HTTP_ENV_VARS

HTTP_SERVER_VARS shows only two elements (PHP_SELF and PATH_TRANSLATED)
however if I turn on register_globals then I can see all the elements of
HTTP_SERVER_VARS in the global scope....but what happened to those elements
being in HTTP_SERVER_VARS with register_globals off and track_vars on?

I had heard at one time there was supposed to be HTTP_STATE_VARS and/or
HTTP_SESSION_VARS


-Dave