+1 on the general idea of the pitch. It's important to have per-target control over the Swift language version.
Apologies if this isn't the thread to debate this point, but I find it very surprising that the default language version of the Swift 6.0 compiler is not Swift 6. Is this the plan for the actual Swift 6.0 release?
Does this mean that going forward, we'll have to pass -swift-version 6 to all CLI swift/swiftc invocations if we want to use Swift 6 features? I would find that very odd. Or is there a plan to change the default in a later Swift 6.x compiler release? (which would also be odd)