Some short updates on design progress (@dholms.xyz can you turn the original post in to a “wiki post”? I think that is just a config flag):
Public spaces: pretty confident we aren’t going to make any big changes here. No re-distributable cryptographic commitments, no space data on firehoses, repo hosts require space credentials for all space repos (even if “public”). As a small change, will probably update space credential endpoint so that both delegation token and client attestation are optional: that makes it clearer how to fetch “public” spaces w/o an atproto account (if the space authority allows it).
Repo serialization: expect to ship with STAR files not CAR files
DPoP: switched to HTTP Message Signatures last week
Sync scaling/reliability: changes shipped last week
Cryptographic commitment: think we might need to do proper Diffie-Helman (then KEM for post-quantum). That would mean publishing an addition key in all DID documents 
but not the end of the world. Also want to iterate on which fields end up in the repo commit metadata object, and which end up as an HTTP header.
URI scheme: still furiously debating 
Simplespace configuration: have a thread going over here: Updateable space policy by matthieusieben · Pull Request #119 · bluesky-social/proposals · GitHub , probably should have been a forum thread instead
Have not started on a couple of the other questions yet. But generally making progress and feels to me like we are on-track to have most of these resolved by end of October, and to be able to ship some time in November.