Clip Timeline adds accurately timed sequential thumbnails of your clips — the whole clip’s action at one glance. Can be used as an editing assistant, or just for show!
Mark your storyline with Titles to indicate chapters. Easier to see than the standard chapter markers. Rename the title to the chapter title. Time length and progress bar is all automatic, no keyframing!
Requires FCPX 10.4.10 or higher but can be backdated to version 10.3.