MacOS X Release Notes
In the first stable series of releases that supported Mac OS X (GnuCash 2.2.9, 2.3.x, and 2.4.x) there were some differences between the Mac OS X releases and the others. Those differences were detailed in special release notes which were copied in the wiki for wider availability. The wiki copies have been removed as being obsolete. In the unlikely event that someone installs one of those obsolete Mac GnuCash bundles they'll find the special release notes in the dmg.