After reading the release notes of Qubes 4.0-rc2 I noticed, that the USB VM was missing. This turned out to be due to a known bug, that occurs when an USB mouse is present while configuring Qubes. In that case the option to create a USB VM is not shown. So I did a clean reinstall and configuration without a mouse present. Now there is a USB VM.
However, there is a problem. The USB VM very often does not start with the error message: Start failed: internal error: Unable to reset PCI device 0000:03:00.0: internal error: Active 0000:03:00.1 devices on bus with 0000:03:00.0, dot doing bus reset. This problem is probably worth a separate topic. -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/66cb0c31-1f9e-487c-b431-4d0ef302baec%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.