I went to
https://lists.gnu.org/mailman/listings/qemu-devel and entered my email and clicked unsubscribe. Then was redirected and clicked unsubscribe again. At the top of the page appeared "If you are a list member, a confirmation email has been sent." I did this at 17:11 (sorry, I don't have more precise time info)
I checked my Gmail inbox (search is:unread) and I don't have a message from the list to unsubscribe. I have tried many times, sorry, I should have sent this earlier.
If you figure out that actually I was doing something wrong, would you be so kind as to letting me know what it was?
Many thanks for your help,
Maria.