Few days ago there was a thread about showing/hiding FX on fcp.co.
Same time I got some mails from FCP users whether my old tool for FCP would work with FCPX.
This old one wouldn't work cause of the differences in XML. But since 10.1.x the XML's features come closer to those ones from legacy – though even Apple states that they aren't perfect.
But finally I decided to bring back my old app to new life.
The app searches for everything which XML internally is an "effect". The count of usage, the name, the user visible type and the FCPX internal usages are listed. Optional you can show the clip names which do use a certain "effect" – except for transitions. Selecting a clip name will set the clipboard to this name and you can use the "find" in FCPX,
The app allows to enable/disable "effects" or just to remove them. These actions are immediately saved to the XML.
The XML can be imported into FCPX and will create a modified timeline.