When I bought the house it had a firepit built in a concrete area of
the backyard. It is built with bricks and holds water when it rains.

The previous owner told me he never used it, and disclosure says there
is no permit for it.

Here is the problem. It has a gas line running into the fire pit
(appears to be from under ground) It has a nut at the end of the pipe,
and just near the pit there is a plate on the ground with a couple of
tiny knobs on the ground that's has label "LP"? or something, is this
a valve control of some sort?

I havn't trace where this pipe is coming from, might be tapping from
the gas line in the house under the crawl space and running below the
backyard concrete slabs?

The pipe is also just steel and it is rusting. I want to figure out
how this thing works. I wouldn't mind cutting off the gas pipe from
the possible "tee" inside the house and capping it off there. I
wouldn't mind it being just a regular log burning pit if I have to..

Do I need a burner or some sort to try it out? Also what do I do
about the pipe being corroded?