"Delete all" when restoring a backup / "Replace from backup"

Currently, "Load contents of a backup" appends rather than overwriting. This is good for data safety. However, I switch between development and production versions periodically, and have to manually delete the old entries when I do so. I would like an option to either delete all, or to replace the existing saved tabs with the contents of a backup instead of appending the backup to what is saved.

Does anyone have a use case for "Delete all" other than restoring a backup? If not, I would prefer restore-with-replacement, since it is less likely to be triggered by accident (you can always hit Cancel in the "Open" dialog box).

Start by tracing the existing “Load contents of a backup” flow and the “Open” dialog mentioned in the issue. Compare the current append behavior with the requested replacement or delete-all behavior, including the Cancel path. Done means a backup can replace existing saved tabs safely without accidental deletion.

Written by the indexing model from the issue text.