This is the MacOSLib project for Real Studio (http://www.realsoftware.com)
It provides a lot of OS X specific functionality that the standard framework doesn't offer.
It even has some cross-platform functionality in order to access Mac specific data on Windows and Linux (e.g. plist files).
To use it in your project, open the macoslib.rbvcp file in the IDE, then select the "macoslib" folder inside, Copy it and Paste into your project.
Attention: Do not attempt to drag or import the macoslib folder from disk into your project - that won't work (see feedback://showreport?report_id=23455)