One of the users on our website reports the following HTTP_USER_AGENT:
Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; GTB6; .NET CLR 1.0.3705; .NET CLR 1.1.4322; Media Center PC 3.1; .NET CLR 2.0.50727)
I cannot figure out what the GTB6 bit means. Google searches are pointless. Can someone explain what GTB6 means and, ideally, point me to a website that explains each part of the user agent, for the uncommon and infrequently seen parts?