DC Circuit MON & GL versus GH on thermostat

Hello,

My name is Jacob. I am new to RVing. Just got a 2022 Palomino/Forest River Puma 289BHS.

I'm planning on doing some electrical upgrade and smart home installs. A couple of things are confusing me though:

1) A DC branch circuit is labeled "MON" (see picture) and I'm having no luck figuring out what that is for. It has a 15amp fuse on it, which is a decent sized circuit for an RV. Any idea what it is?



2) The thermostat has 6 wires, and I can identify 5 of them. But either GL or GH controls the propane furnace. The RV has two tanks. So is GL one side and GH the other? Or is there a different heating accessory (like a heat pump) on here? To install a smart thermostat, I need to what they are. Any idea?



Thanks in advance,
Jacob