I guess nothing is stopping us from deliberately publicly-sharing any google docs design document link that we feel is ok for public consumption, but that's a bit of friction and I don't think anyone's been consistently doing this - I certainly haven't been

I’m not sure I follow. I liberally link to the Google doc in my PRs

Public sharing is fine. I'd be in favor though of moving do markdown docs checked in to the repo. That would allow a normal PR to suffice as the design discussion plus have explicit sign-off. The biggest upside besides all that is you can actually reference real code well.

@hundreds-father-404 can random people who are coming across the pants project access them? and be guaranteed to access them on a long-term basis?

I always mark mine as “anyone with the link can comment”

I'm not sure what I do, I wasn't thinking about it until now

Yeah, I just “anyone with the link can comment” that kind of thing

at Twitter, we have perennially had issues deciding early enough in a design process that something needs upstream involvement