What is the difference between StudlyCaps and CamelCase?

Question

PSR suggests, method names MUST be declared in camelCase and class names MUST be declared in StudlyCaps.

Answer 1

CamelCase is where the first letter of each sub-word in a name is capitalised. The first letter of the whole name can be upper or lower case, and is generally (always?) lower case in programming.

StudlyCaps is a little weird. There are capital letters, but they can be at any letter according to some rule, not just the beginning of a sub-word. The classic example is (was) HoTMaiL.

My understanding of the PSRs is that their intention is that each sub-word should be capitalised in both instances, with classes having an initial upper-case letter and methods an initial lower-case letter.