1994 Camry, 4 cyl, 240K: I have exhaust coming from the front mesh section of the exhaust pipe. It is the mesh section nearest the front of the exhaust pipe just behind the vertical section that comes down from the engine. What is it?

I assume it is covered in mesh to allow it to bend slightly so is it not a tight connection there?

Yes, it's a flexible coupling so that engine movement doesn't stress the exhaust system. It is a known weak spot in the exhaust system.

Is there a gasket, rubber boot, or something that I should/can replace there? I don't see anything about it in the Camry manual.

No, the whole piece needs to be replaced. It is called the downpipe or flexpipe. Goes for about $100 at the parts store.

I'd also opt to buy stainless steel nuts, bolts, and washers, plus new upper and lower pipe gaskets.

Finally, I'd suggest good flanged nuts for the upper connection that have the serrated edge to help keep them from backing off or at least a washer/lock washer/nut combo. A dab of loc-tite helps, too. For some reason, mine would always vibrate loose.