Not sure if this is the right place to post this, being a relative newby in the Qubes-os forum.
Kali Linux now works a treat after a previous failure to upgrade. Apologies, no details about the failure to update, which I intended to reproduce and then post here, but now of course, it has sorted itself out and works fine, while I failed to note the failure details. The usage VM reports that there are a couple of applications missing and advises me to re-install those in the template VM. I am not too concerned about those.
I installed signal-desktop in the debian-11 template VM, temporarily connecting it to sys-firewall in order to be able to [wget -O- https://updates.signal.org/desktop/apt/keys.asc]. The system warned me that I am very naughty doing that as it basically breaks the Qubes-os security policy. Signal-desktop works fine for messaging in the debian-11 usage VM. I haven’t had occasion to test telephony with signal yet. I followed the instructions on
Signal >> Download Signal → Not on Mac?