Matroska is an audio/video container, often found with the .mkv extension. It is also the basis of the WebM container.
The IETF standards repositories can be found at https://github.com/ietf-wg-cellar/matroska-specification and https://github.com/ietf-wg-cellar/ebml-specification
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