The house was built in the 20's by a commercial plumber who put in some more commercial-style amenities including some state of the art for the era tankless flush-valve toilets. I love them, wife hates them.
Quickly tried to find a picture of this, but don't know what exactly i'm looking for. Can you post a link?
edit: It's just like what you'd find in any modern commercial building in the US, just with a much older form factor of toilet. When we moved in I got curious why most new homes don't have them. Found out that they don't use any more water than a normal toilet, but they do require a higher water flow rate. The high flow rate requires at least a 2" water main into the house (which we have), while most modern residential construction uses a 1" or less.
Holohan describes the differences here: https://heatinghelp.com/systems-help-center/a-steam-heating-...
He also points out that the failure point of the system you have is that the "steam traps" tend to fail frequently and silently. The system still heats, but runs less efficiently. He says the traps typically have only a 3 year lifespan.