The only definitive answer I've found is here: https://developer.apple.com/forums/thread/12097. But source not cited, and maybe something's changed in the intervening 8 years. I hope so, as I'd like to collect things like accuracy. Having external position paired with internal meta data seems like an odd and limiting choice.

Adding libswift_Concurrency.tbd did not work for me on Xcode 13.2 (not even RC). I was forced to go back to 13.1, which worked, and hope Apple can get it resolved soon.