Apple today seeded a new macOS Big Sur 11.0.1 beta to developers for testing purposes, with the new beta replacing the existing macOS Big Sur 11 beta 10 update that was released two weeks ago.
The only explanation that makes any sense is that 11.0 was “shipped” as the factory OS for some new hardware, which may well be the first Apple Silicon Mac(s), queuing up for a pre-Thanksgiving announcement. There could be new Intel Macs in the pipeline too — there almost certainly are — but you would think those might not require Big Sur.