I have reviewed this document as part of the Operational directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments were written with the intent of improving the operational aspects of
the IETF drafts per guidelines in RFC5706 .
Comments that are not addressed in last call may be included
in AD reviews during the IESG review.  Document editors and WG chairs should
treat these comments just like any other last call comments.

Summary:

   This document defines the Extensible Binary Meta Language (EBML) format as a generalized file format for any type of data in a
   hierarchical form.  EBML is designed as a binary equivalent to XML and uses a storage-efficient approach to build nested Elements.
   Similar to how an XML Schema defines the structure and semantics of an XML Document, this document
   defines  EBML Schemas to convey the semantics of an EBML Document.

 The draft does not impact operational considerations listed in RFC 5706. 
However similar to concerns expressed in  GENART review the document is standard track and defines general purpose markup language. 
If this is applicable beyond cellar to other protocols then it needs wider review.