[ttml2] Pull Request: Add #metadata-version-2 feature designator (#491).

skynavga has just submitted a new pull request for https://github.com/w3c/ttml2:

== Add #metadata-version-2 feature designator (#491). ==
Closes #491.

See https://github.com/w3c/ttml2/pull/508

Received on Saturday, 23 December 2017 23:13:23 UTC