Development discussions and questions take place on the Xiph.Org Opus mailing list (firstname.lastname@example.org). Discussion related to the IETF process happen on the IETF codec working group mailing list (email@example.com).
For archives of recent discussions, try:
If you find a bug, please report it in gitlab.
For anything non-confidential (e.g. general questions about Opus), please use one of the mailing lists above. For confidential enquiries, you can contact one of the following developers directly: