Flatpack does not require user namespaces. bubblewrap, the tool Flatpack uses to secure things, can be installed set-uid and can then setup the sandbox without

Flatpack does not require user namespaces. bubblewrap, the tool Flatpack uses to secure things, can be installed set-uid and can then setup the sandbox without the user namespaces. Chromium-based browsers also include own setuid tool to setup the sandbox if the user-namespaces are not available. Even podman could have used something like that. But I guess RedHat assumes that the user namespaces are solid these days are do not bother…