I think the title says it all but if needed - I’ll edit this. Of course I googled but I got nowhere. Google results were total shit. Google won’t help me if I don’t know the exact name for that fucking thing. It’s a very stupid design choice. Five regular old push buttons would be so much better.
About an hour ago I managed to stick it back on but I’m nearly 100% sure it’s going to fall off again in week or two if not far sooner.
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Edit
I don’t mean part of the unit itself. I mean just the thin plastic cover over the buttons that’s ~3mm thick.
I would call it either a control panel or a button panel, but would defer to whatever the owner’s manual calls it in a schematic.
bizarrely, those thermostat controllers can be pretty cheap to replace and totally in the realm of DIY.
the wires leading to HVAC should be color coded and sometimes are tagged.
just saying if trying to fix a cheap component becomes too infuriating (because they are often cheaply made).
anyway, good luck