For production or daily use, consider newer Android-x86 versions or alternative Android-on-PC solutions.
This specific release is based on (API level 23). The “r1” designation indicates it is the first stable release of the Android-x86 6.0 branch.
Overview android-x86-6.0-r1.iso is a disk image file of the Android-x86 project, a port of Google’s Android operating system designed to run on devices powered by x86 processors (Intel, AMD, VIA, etc.) rather than the usual ARM architecture found in smartphones and tablets.