Download of GuitarLayers 2.7 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software belongs to Education Tools. This Mac app is an intellectual property of moreOrLess music. We recommend checking the downloaded files with any free antivirus.
From the developer:
GuitarLayers is a professional macOS guitar learning software application. It allows you to visualize and manage, scales, chords, and arpeggios shapes through a fully parametric control interface. Moreover, it enables you to visualize harmonic concepts by overlapping shapes on the guitar fretboard thanks to a powerful layering system.
You may want to check out more software for Mac, such as PianoRoll, dvcUniversity or RFB&D ReadHear, which might be related to GuitarLayers.