What
Claude Code installs plugins and tools by swapping in a new "extraction" (an unpacked copy of the files) and moving the old one aside as a backup. If that swap fails and the code tries to restore the old backup, it now first checks whether a newer extraction has already been put in place. If so, it reports that a newer extraction is live and the backup was simply moved aside, instead of reporting a generic restore failure.
Why
This prevents a confusing false alarm: previously any error thrown while restoring the backup was treated as "could not restore," even when the real story was that a newer version had already taken over and restoring the old one wasn't needed or possible. The new message tells you what actually happened.