It probably becomes 1m 60s. I’ve had microwaves do it both ways, either having it only be in seconds or having seconds for two digits.

Edit: I’m dumb and very tired from Holidays, I’m leaving this up anyways though.

I have an analog microwave from 2007. It just has a mechanical timer

I dunno. I’ve never put in a time on my microwave - i just use the add button. Does it give you a minute and 60 seconds. Thats weird.