Apple has released a supplemental update for macOS 10.15.6, as well as iOS 13.6.1 and iPadOS 13.6.1.
To download the macOS supplemental update, go to System Preferences and click Software Update. According to Apple, the update fixes a stability issue that could occur when running virtualization apps. It also resolves an issue where an iMac (Retina 5K, 27-inch, 2020) may appear washed out after waking from sleep.
Apple has released iOS 13.6.1 and iPadOS 13.6.1. You can download the iOS and iPadOS updates by opening the Settings, choosing General, then Software Update.
According to Apple’s release notes, the updates: include bug fixes: address an issue where unneeded system data files might not be automatically deleted when available storage is low; fix a thermal management issue that caused some displays to exhibit a green tints; and fixes an issue where Exposure Notifications could be disabled for some users.