They do not have a strict "no binary blob allowed" policy. Concerning VMs, they have a policy of minimal modifications: https://doc.qubes-os.org/en/latest/introduction/faq.html#wha...

The dom0 is based on Fedora and has the Fedora's policy for firmware blobs. See also: https://doc.qubes-os.org/en/latest/introduction/faq.html#wil...