I thought microsoft has been super generous in that regard. winrar has been out for 25+ years, effectively giving winrar a long runway to collect. It's about time this is incorporated into windows os.

Libarchive (the backend for this functionality) cannot create rar archives, only read them.

So the company that developed it will be fine. You will still need winrar.

??

This will only have RAR extraction and UNRAR.DLL was deliberately not commercial.