Why does Flatpak not require a password?
Flatpack is installing software, right?
Example: my distro (Ubuntu based) installed Brave and Chrome browser updates today, no password was required.
Isn’t sudo, or otherwise admin access, required to make system changes?
The per-user data is located under $HOME/.local/share/flatpak/, it doesn’t require sudo. From the reasons to use Flatpak is the rootless install:
Rootless install: elevated privileges are not required when installing a Flatpak application or a runtime.