Not exactly a “kitchen appliance”, but they didn't fit well in any other category. These are the appliances which heat water for the purpose of distribution throughout a building. Apparently, some of them run Linux + ARM(?)…

There is an Ethernet connection on the back of the controller module

It’s postulated that this thing’s controller can run doom, and apparently they can be purchased separately, although what controller exactly is not specified.

https://www.reddit.com/r/linux/comments/k0z196/my_boiler_runs_linux_on_its_touchscreen_controller/

https://www.manualslib.com/manual/790246/Ibc-Technologies-Sl-20-115.html