[ttml2] Pull Request: Correct and clarify #extent-root-version-2 (#1027).

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

== Correct and clarify #extent-root-version-2 (#1027). ==
Closes #1027.

See https://github.com/w3c/ttml2/pull/1110

Received on Wednesday, 5 June 2019 20:05:11 UTC