These are three different button mechanisms.
-The Kailh-Blue is very tactile, easy to press and clicks rather loudly.
-The Kailh-Brown is also tactile, but does not click as loudly.
-The Kailh-Red, unlike the other two, moves linearly.

Enclosed I send you an article where you can see three mechanisms. Maybe this will help you.

https://www.keyboardco.com/blog...