Now from here you might think this is alps snap action, and I did too initially, but unfortunately this doesn't appear to have anything to do with alps. Unsure why it would have this mount then, I assume the mount and caps are an Olivetti thing rather than an alps thing then.
The switches are descrete units held (kinda loosely) into a switchplate over top of the PCB.
there was a plastic/rubber contamination shield between the switches and the platesprings, but over time it became both brittle and kinda sticky so I have removed it as best I can but it's pretty well stuck to the plate springs in a few places.
The PCB has a bunch of these plate spring units soldered in over a central peg. when the switch is depressed the slider compresses a coil spring which pushes on a lever arm that presses on the plate spring. The plate spring snaps and inverts, bridging the plate spring and the peg and closing the circuit. It's a pretty solid design in principal and execution and if theses were in good condition they would likely be very nice.
However, any plate spring switch without sufficient care taken to prevent the plate from being bent out of shape (especially like this switch, where bottom out puts significant force on the spring itself) will eventually wear out such that the actuation of the switch gets wonky. My board is especially bad about that with switches varying in tactility, volume, actuation distance, and actuation force pretty wildly. I tried to fix a few by bending the springs a little for ones that clicked very weakly and this did not have a consistent effect. It made them feel and sound different but not better. I can't really recommend these if you want to have something to type on considering the issues with inconsistent wear, but they're a neat switch for collection I suppose and if your typewriter is actually working properly it would likely be a fine typewriter.