It also happens when the hosts file is messed up and the system can’t resolve its own hostnames. Opensuse used to be pretty notorious for doing something odd to the hosts file by default that really only affected Firefox.
Edit: the increased security they’re trying around the browser might also be triggering that local resolution issue
I appreciate the clear marking that something is unverified, but don’t think disabling by default is the right move. As others have mentioned, most of the software in the distribution is also unverified.
Worried in the sense that having a backup is a good idea, most filesystems do not have much protection from a file becoming corrupted, but random corruption is rare. Personally I like an automated, regular cloud backup to B2 and also do a local one that is easier (faster) to restore. For local, I prefer Borg (or rather the Pika Backup frontend) because you can easily store different dates while also benefitting from file deduplication.
The Mozilla Foundation is doing that. They legally cannot focus on browser development. Donations to the Mozilla Foundation go to the Mozilla Foundation.
The Mozilla Corporation is making the changes. It has zero control over the Mozilla Foundation. The Mozilla Corporation does not accept donations and is a for-profit company.