Simplify the following text for a Grade 11 native English-speaking person.
Original: Debian is a computer operating system composed of software packages released as free and open source software especially under the GNU General Public License and other free software licenses . The primary form , Debian GNU\/Linux , which uses the Linux kernel and GNU OS tools , is a popular and influential GNU\/Linux distribution .
Simplified: Much of the application and utility software was done by the GNU project , so Debian Linux is more correctly called `` Debian GNU\/Linux '' .