A long time ago, I had bought a keyboard at a thrift shop, despite not liking the layout of its keys, because the keys where clicky. Unfortunately, one of the keys was broken. However, this is not all bad, as if I intend to try an advanced keyboard customization project, I'd rather use a defective keyboard for parts if I can.
The keys worked on a unique mechanical principle; an element shaped like the surface of the piston/rotor in a Winkel Tripel engine is advanced each time the key is pressed. This doesn't appear to be pictured on the Japanese page that is cited as the main authority on ALPS switches and their lookalikes. (EDIT: the element doesn't actually rotate 120 degrees each time; the switch is actually more conventional than that, and my impression was an illusion. It looks most similar to the Macally switch pictured, but it is different.)
From visiting this site - as I had never disassembled a Mac keyboard - I found that the switches in the keyboard look like ALPS switches. They have blue stems.
The keyboard was made in Taiwan by FAME, and has FCC I.D. GOG3YLTH-5539.
It has a small hole in the base for a switch labelled X/A, presumably for switching between connecting to an XT or an AT, so it is an early keyboard.
