[ttml2] Pull Request: Define alterability of initial values; specify that tts:ruby is unalterable (#1140).

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

== Define alterability of initial values; specify that tts:ruby is unalterable (#1140). ==
Closes #1140.

See https://github.com/w3c/ttml2/pull/1146

Received on Friday, 30 August 2019 06:54:18 UTC