Flathub aims to be the place to get and distribute apps for Linux. It is powered by Flatpak which allows Flathub apps to run on almost any Linux distribution.
How does it stack up against traditional package management and others like AUR and Nix?
On the one hand I like the basic idea, on the other hand I think that some fundamental problems aren't fully solved yet. There big use case are passkeys and direct password manager integration – neither mesh well with the idea of software that isn't allowed to talk to most of the system.
I'm certain that this will be resolved at some point but for now I don't think Flatpak and its brethren are quite there yet.
Not sure what that means, but probably native messaging, a biig missing portal.
Flatpak has an Inter-process-communication permission, so software could absolutely be opt-in allowed to talk, while keeping security for the rest. Apps cant see each others ~/.var/app/org.app.name/ storage though, never.