Android 12L Beta 2 brings bug fixes and optimizations, as well as fixes for refinement of the resizing of icons relative to the screen size.
Thanks to the new files it finalizes APIs and system behaviors for this version of Android so that developers can begin focusing on finalizing their apps with compatibility of the new Android build. For reference,

Android 12L is a mid-cycle Android build meant to optimize Android’s usability across different form factors and devices.

The update is available for Pixel 3a XL and all new pixels and is being send right now to all supported devices.