How a class extension works as a means of implementing private methods

Question

I believe a popular way to declare "private methods" in Objective-C is to create its class extension and declare methods that you would like to make as private.

I would like to know more in detail on how an class extension makes the methods work as private.

• Update: I asked this question with the term empty category which is incorrect. I now changed it as class extension

Answer 1

That's not an "empty category", it's a class extension. Read Bbum's explanation of them at the link I provided.