Hello, i have never read about this so i feel i should share, i had bought Kailh choc switches for my custom trackball build, and while playing around i found out that the footprint lined up perfectly on proto/perfboard, need to either let them hang on the side of drill larger holes for the plastic legs but the electrical contacts line up on a 2*3 grid and the plastic legs do somewhat also line up.
I wonder if it was a design consideration by kailh or just an happy little accident. fell this could be useful for others building custom boards.