User-Agent Profile - Esato archive

Posted by johanw
I am trying to figure out how the User-Agent Profile Repositories work. How do you access them? Are info about which user-agent profile the phone using sent in the HTTP-request? Can this info be read somehow and then read the phones xml-page to find out what for example what screen size the phone have and direct it to the correct page? Or do you need to build your own database of info?

A lot of questions, but any little bit of information will be greatly appreciated for me to understand this puzzle.