The Best Body Retrieval Algorithm determines the best format of a message body. This algorithm enables clients to determine the format of the message body that is most like the original message, and maintains the richness of the text and formatting in the original message.
Exactly how the server converts message text from one format to another, and to what extent formatting is preserved in the conversion, is implementation-dependent.
Sections 1.6 and 2 of this specification are normative. All other sections and examples in this specification are informative.