Chain and screw drives
The housing here centers on 1982, which puts a lot of these garages on chain-drive and screw-drive units from the 80s and 90s, plus a second wave of belt-drive replacements from the 2000s. A home built in 1982 almost certainly didn't come with a factory opener still running today - it's been replaced at least once, sometimes with mismatched rail length or a logic board that doesn't talk to the original wall switch.