As of Qubes-Whonix 10, Qubes-Whonix Whonix-Workstation TemplateVMs are capable to connect to open internet (over Tor).
Is it a bug or feature?
I guess we should keep connections to torproject.org (Tor Browser updates, perhaps anonymity/connectivity check), Debian, Whonix and Qubes repository allowed, but block the rest? Similar to Qubes' default Fedora TemplateVM?