Hi there!
In the world of mixer-less istio, we are going to rely on peer-to-peer environment metadata exchange. Please take a look at the doc describing the mechanics and leave a comment if you have any thoughts on the subject.
https://docs.google.com/document/d/1bWQAsrBZguk5HCmBVDEgEMVGS91r9uh3SIr7D7ELZBk/edit#
Thanks!