Plymorph

Mozilla's Firefox Sync service uses end-to-end encryption, meaning the company provider cannot decrypt user data, though the actual data stored on disk remains unencrypted. For Linux file access, standard setup dictates that any process running under the same user can access files within the home directory.

The debate centers on what level of privacy is actually achieved. Some users, like folekaule, argue that only system-level measures, specifically encrypted home directories, provide true security, dismissing application-level obfuscation as a false guarantee. Opposing this, users like terribletortoise and Branquinho state that the current file visibility is the 'expected' and standard behavior for Linux, suggesting that AppArmor, SELinux, or containers are the correct tools for additional restrictions. kylekatarn confirmed the E2EE aspect of Sync with a local password. Furthermore, steel_for_humans noted self-hosting options exist for maximum control.

The community consensus splits sharply: either filesystem encryption is mandatory for any claim of privacy, or the default OS behavior is acceptable and sufficiently restricted by user-space tools. The fault line runs between demanding perfect, kernel-level isolation versus accepting standard per-user process boundaries.