Inverters come in 2x2x2 flavors but we are only interested in two of those.. Factory installed or after market, Large and small (WHich often condenses down to one)
Factory installed is often a 300-600 watt, this can be"hidden" in assorted places. Runs the main TV and support electronics, not much more Can be hard to find. but look for a heavier than average wire to the battery.
After market can be 300-3000 watt, now the smaller ones can be at a distance from the battery but the bigger ones get parked downright near the batttery and are fed with cables larger than your thumb.
Of course.. that is if there was one installed.