A question I've been meaning to ask for ages, more theoretical than anything else.
I'm fully versed in developing Extensions using the normal Magento module file structure. I've noticed though when looking at some of the Mage 'extensions', that some contain a /Controller directory. Whats the purpose of these controllers and how do the differ to the ones used normally within the /controllers dir?
I can see the names are structured differently, so I'm gathering they're auto-loaded in a different way, but what purpose do /Controller classes serve?