Apple has released its second build for the Big Sur macOS 11.3 beta to developers for testing purposes.
Developers can head over to the official Apple Developer Center to download the beta file and configuration profiles, as well as get OTA updates when subsequent changes become available.

The first beta for Big Sur 11.3 was launched February 2 along with first betas of other Apple operating systems. Release notes state that there have been bug fixes and improvements, notably Reminder sorting changes, a new Listen Now live event and ‘Made for You’ shortcut in Apple Music and a redesigned tab for Apple News+.
Full release notes are available to view on the official Apple developer site.
Beta versions of operating systems are not recommended for primary or important devices as it can lead to system instability and data loss. Developers should install them on non-important or secondary devices and complete a backup first before doing so.