On Oct 30, 2015, Thomas Tempelmann has released a new version of the Spotlight importer for Xojo.
It allows Spotlight to search projects saved by the Xojo (and Real Studio) IDE.
The importer used to be included in Real Studio and early Xojo IDEs until about 2 years ago. This version by Thomas Tempelmann is functionally the same, as a standalone plugin, and updated to support the latest Xojo project formats.
More information and download here: http://www.tempel.org/RB/SpotlightImporter