Final Cut Pro

Final Cut Pro is video editing software developed by Apple for the Macintosh. Projects for Final Cut Pro version 1-7 saved in a binary format with the  extension, projects files did not contain the media for the project. Final Cut Pro X was redesigned and the project format changed to an XML based format.

File Identification
Final Cut Pro files with a  extension have the hex values  for the first 5 bytes, or   in ASCII. Which is probably related to the software's original name "KeyGrip".

Final Cut Pro files can be exported into an Apple Exchange XML format, versions 1-5 for use in other software, as well as migrating to new FCPX format.