Fedora and Debian have similar philosophies. FOSS only, packages must be built from source, no vendored dependencies. So they have similar policies regarding security and Fedora Flatpaks align closer to that than Flathub.
I believe Debian also doesn’t ship patented codecs in their main repo.
I don’t think nonfree is enabled by default. Though I guess the repos are still hosted by debian, unlike RPMFusion. Though Fedora does treat it as semi-official given that parts of it can be enabled during first setup.