Apple has released a beta version of macOS Big Sur 11.6.1 for users enrolled in the beta testing program for MacOS Big Sur.
The beta update is said to include security fixes, and hints at what the final version of macOS Big Sur 11.6.1 will include for Mac users running Big Sur.
While most Mac beta testers are probably running macOS Monterey beta 8 instead of any Big Sur beta, the update is available via System Preferences > Software Update for those who are.
Presumably macOS Big Sur 11.6.1 will be finalized and released to all Mac users in the near future.