You're looking for a report on Cakewalk by Bandlab (formerly known as Sonar) on a Mac with OS X, specifically about downloading exclusive content. Here's what I found:
The Mac Prototype: This was a collaboration with CodeWeavers using CrossOver technology to run the Windows version on Mac. It was limited, lacked external plugin support, and is no longer supported for modern macOS versions. cakewalk+sonar+mac+os+x+download+exclusive
Pro Tier: Requires a BandLab Membership to unlock high-DPI support, premium ProChannel modules, and advanced mixing tools. You're looking for a report on Cakewalk by
The prototype is available as a free download for those looking to experiment with the SONAR workflow on older Mac systems: lacked external plugin support