Motif DND protocol overview desired

[Vlad Harchev <hvv hippo ru>]

 Hi, 

 Sorry for offtopic, can anybody provide links to some high-level
description of Motif DND protocol implemenation (it's needed for adding Motif
DND support to some widgetset). Of course I know that gtk provides Motif DND
support, but it would be better to have some overview than to reverse enginer
the gtk code.

 Thanks!

 Best regards,
  -Vlad