Some models of switches. Neat if you want to see how a switch looks in your keyboard when you are modeling it.
Remember that the measurements are not exact. They are a "best effort" to reproduce how the things looks. Using a caliper and going by eye for all the measurements so things can be off. Hopefully not too much.
Basically to just model different kinds of switches I get a hold of. I've found that it is sooo much easier to design a keyboard when you can import switches and keycaps to see how much space you actually need for things.
CERN-OHL-S