Imagine your friend that does not know anything about linux, don't you think this would make them not install the firefox flatpak and potentially think that linux is unsafe?
I ask this because I believe we must be careful and make small changes to welcome new users in the future, we have to make them as much comfortable as possible when experimenting with a new O.S
I believe this warning could have a less alarming design, saying something like "This app can use elevated permissions. What does this mean?" with the "What does this mean?" text as a clickable URL that shows the user that this may cause security risks. I mean, is kind of a contradiction to have "verified" on the app and a red warning saying "Potentially unsafe", the user will think "well, should I trust this or not??"
No. If you put a warning on every app (except for the most trivial ones that don't actually do anything useful) then the warnings mean nothing. The become something more than ass-covering legal(ish) BS.
Apps could start improving to remove the warnings…
What do you mean by "improving"? This alarming warning appears because Firefox requires permissions. Let us look at the permissions listed there:
App permissions should not be about "this app cannot be trusted because it asks for scary scary permissions". They should be about "take a look at the list of permissions the app requests and determine whether or not it make sense for such an app to need such permissions".
To 1.:
driinstead ofallwould handle hardware-accelerated rendering. Then some webcams or controllers won't be accessible though. This one's a bit complicated, since the necessary portals for e.g. generic USB device access aren't yet there.To 2.: portals should be used instead of that. Using them doesn't require these permissions.
To 3.: click on details and see. This is Flathub making it easy to understand for users.
Permissions should make clear whatever dangerous things an app can do. If not, why do all this effort of isolation? Firefox could delete everything in downloads, either by accident on Mozilla's side, or a privilege escalation. If the app used portals instead, it couldn't, at least without user interaction. Or a browser security vulnerability could open up any USB devices to webpages. It's all about what could happen with granted permissions. And these can 100 % be fixed in at least some way.