How many amp-hours?

FLA and AGM batteries will vent and for safety reasons need to be outside, not inside. If you want batteries inside you need to use LifePo4 batteries.

Is that will vent or can vent?

I am no battery expert by far but I did read alot before I bought my VLRA AGM battery..They use VLRA batteries on Nuclear submarines/on wheel chairs and floor scrubber machines,all used and stored inside..

My understanding is,they can vent if misused?..That was more of a question than statement..

VRLA stands for “valve-regulated lead-acid.” It’s a general term for a lead-acid battery in which there is a safety valve to control the release of gas from the battery. Under normal circumstances, the valve is closed, which allows the hydrogen and oxygen produced during charging to recombine inside the battery, preventing loss of electrolyte. If the battery is overcharged or charged too fast, the valve can open to allow some gas to escape.

And this..

VRLA batteries are used extensively in power wheelchairs, as the extremely low gas and acid output makes them much safer for indoor use. VRLA batteries are also used in the uninterruptible power supply (UPS) as a back up when the electrical power goes off.

VRLA batteries are also the standard power source in sailplanes, due to their ability to withstand a variety of flight attitudes and a relatively large ambient temperature range with no adverse effects. However, charging regimes must be adapted with varying temperature.[16]

VRLA batteries are used in the US Nuclear Submarine fleet, due to their power density, elimination of gassing, reduced maintenance, and enhanced safety.[17]

It seems if a person used them inside the RV by a well ventilated area,they would work just fine under normal circumstances..I have seen many threads on using an AGM battery inside an RV,some right here on this forum..There are a ton pf people that do it and others say not to kinda like the Catalytic heater debate..