I'm not 100% sure what they are installing on the newest ER's but the first 150 or so (including mine) use a Lippert step. They aren't awesome, and have a few design flaws (which possibly may have been fixed by now). ER modifies most of them to eliminate one glaring issue. From what I've seen similar steps are on an awful lot of RVs. The ERs have a magnetic switch that will allow the steps to fold down (or up) when the camper door is opened (or closed).
Check out their website and go to preowned, it's been awhile but if you're talking about the little ones on the rear bumper, their trucks appear to use these: https://www.eberhard.com/details/folding-steps/585809-series
I think they use powered amp steps or something similar for accessing the crew cab.