I'd probably spend at least 20 minutes just to get through how the keyboard works, much more if it's a USB-HID device.

Hah - that is exactly what I did. Someone asked me this question and after 5 minutes in the weeds of the debounce on the mouse click they said "look all we wanted was to find out if you'd ever heard of DNS, let's move on, that was great".

the good ones would usually follow up with, "how much detail do you _really_ want ;D"