Alongside the improvements available with Windows 10 build 18912, as part of the 20H1 development, it seems that Microsoft is also testing a few other changes. According to Twitter user Albacore (via Neowin), the latest flight includes with at least two new visual changes.
Starting with build 18912, it’s possible to create calendar events directly from the Time & date flyout from the taskbar.
Also, in the Delivery Optimization settings page, you can now set the maximum percentage of bandwidth that your device can use to download updates in the background and foreground. In the past, you were only able to set the limit in percentage, but now you can set the maximum bandwidth in Mbps.
These new visual changes are not available for everyone, which could indicate that Microsoft is just testing these features with a small number of participants of the Windows Insider Program, and they may never make it to the final version.