Logic Pro project file
A Logic Pro project file stores an entire project (including its audio files) of the Logic Pro digital audio workstation software. This software package for the Macintosh started out as Notator Logic and became Logic and later Logic Pro, as its original company got bought out by Apple. A reduced-feature consumer version Logic Express has also been released.
The .logic extension was used originally, but was changed to .logicx with the Logic Pro X version in 2013. Newer versions can still open the project files of older versions back to version 5, and can also open GarageBand project files.