[ttml2] Pull Request: Add and update element derivations (#380).

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

== Add and update element derivations (#380). ==
Closes #380.

See https://github.com/w3c/ttml2/pull/805

Received on Tuesday, 29 May 2018 09:15:36 UTC