The tooltip seemed to hint that this tool is able to resolve all manner of gimble-lock situations by untangling the curves (i.e. performing some kind of equivalent-angles resolution, keeping in mind the nearest situations nearby). However, this tool currently only performs corrections for the most basic case when large jump+flip discontinuity artifacts appear in euler rotation curves as a result of rotation values getting clipped to +/- 180 degrees, which arises when these rotation curves are the result of baking some physics sim or so. (Also, fixed an unrelated "replace-all" typo in a comment)