Does Opera Sync fully replace manual profile backup for complete data recovery?

Opera lacks a built-in backup and restore utility, so users rely on manually copying the profile directory or on Opera Sync. The profile location varies by OS and build type, and copying a running profile risks capturing lock files or an inconsistent state. Sync encrypts data with an optional passphrase, and its documented scope excludes extensions, some local-only settings, and certain profile files.

The goal is to determine whether Sync is designed as a complete backup substitute or only as a cross-device synchronization layer. This distinction affects disaster-recovery planning, especially when migrating between machines or recovering from profile corruption.

Which profile components are guaranteed to be restored by Sync alone? Does the sync passphrase requirement create a dependency that prevents offline recovery? What official guidance defines the boundary between Sync and a full profile backup?