Fedora template as default template in Qubes OS? Privacy, anonymity, security of such a solution.

[FranklyFlawless]

Generally no for both questions, although packages in Debian are typically less up-to-date compared to Fedora, and this topic is out of scope for the Qubes-Whonix category:

What to post in this Qubes-Whonix forum and what not.

As a rule of thumb: Everything that happens “inside” the virtual machines is Qubes-Whonix and belongs into this sub forum. Everything that happens “outside” the virtual machine is Qubes and the Qubes help should be consulted. Some examples: EFI → Qubes support Errors by by Qubes VM Manager (QVMM) → Qubes support libvirtError → Qubes support Issues that also apply to Debian based VMs. → Qubes support error: Failed to save domain whonix-ws-dvm to /var/lib/qubes/appvms/whonix-ws-dvm/dvm-savef…