Why was KB4586876 (.Net 4.8 Preview) automatically installed on a production system?

Today (Dec. 18th 2020), my system running Windows 10 Professional 20H2 automatically installed an Update for .NET preview KB4586876, without any obvious reason.

I am asking because I never opted in to any preview or beta program, nor do I participate in an insider preview program or anything else. According to my understanding, preview versions should not be automatically installed on a productive system by Windows Update, but this is what happened on may system anyway.

I would like to know the following:

1. Why does this happen, is there any good explanation for this behavior?
2. Is it safe to uninstall KB4586876 from the "Add/Remove" section of Windows control panel, or will it have any side effects?