The definition of MHEG-6 - (Multimedia and Hypermedia Information Coding Expert Group)

MHEG-6 - (Multimedia and Hypermedia Information Coding Expert Group) - MHEG standards and specifications were developed to increase MHEG-5's performance and access to various external services. MHEG-6 is often more associated with advanced MHEG interactivity.

http://en.wikipedia.org/wiki/Mheg

MHEG-5

MHEG-3 - MHEG regarding scripting.