If you search for
ED444FF07D8D0BF6
the internet is full with people having issues with that.
1
scurl-download https://archive.kali.org/archive-key.asc
2
sudo cp archive-key.asc /etc/apt/trusted.gpg.d/
3
echo "deb http://http.kali.org/kali kali-rolling main contrib non-free" | sudo tee /etc/apt/sources.list.d/kali.list
It’s not doing fingerprint verification. → Verifying Software Signatures - Kicksecure
Bad usability in this case isn’t that something Whonix is causing or can fix.
Upstream documentation still using /etc/apt/sources.list instead of /etc/apt/sources.list.d/kali.list. Upstream documentation isn’t great, I had to combine these two: