JSEP Appendix B (now in IETF RTCWEB WG last call) includes RTCP routing rules:
The plan is for the RTCP routing rules currently in JSEP Appendix B to be published in the MMUSIC BUNDLE draft: https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation
When the RTCP routing rules land in BUNDLE, Section 13.3 on RTCP matching should reference them.
Reference to IETF RTCP Routing Rules
Work-in-progress (not suitable for merging).
Awaits integration of RTCP routing rules into the MMUSIC BUNDLE draft.
Fix for Issue #643