Simplify the following text for a Grade 5 native English-speaking person.
Original: Mac OS X Leopard ( version 10.5 ) is the sixth major release of Mac OS X , Appleâ s desktop and server operating system for Macintosh computers .
Simplified: Mac OS X v10 .5 `` Leopard '' is an operating system made by Apple Inc. for its Macintosh line of computers . It is a version of Mac OS X , and carries the release number 10.5 .