Hi all, I just viewed this good news.
Official announcement: https://www.raspberrypi.org/forums/viewtopic.php?t=274595&p=1663644#p1663644
Andreas Spiess video: https://www.youtube.com/watch?v=zVhYvvrGhMU
and cheatsheet: https://www.dropbox.com/s/6bjx6nlu5sa7bxt/USB%20Boot%20Commands.docx
EDIT 2020/05/22 just to anticipate your next question:
Q: Does it work for HassOS?
A: Not jet (HassOS v3.13 and v4.6rc), but there is a partial solution which gives most of the benefits, just skip to reply n.32