I am surprised that the input of "find and replace" are saved as user preferences via API, the commit message said it was for cross-session, then I think local storage should be more suitable for this use case.
This was introduced 7 years ago, and no tasks were linked, so I have no idea about the context.
By the way, users may expect that their inputs to a private session not affect normal sessions, or "find and replace" inputs to be empty after clearing the browser cache.