Operating systems
Set of operating systems, for which the projects are created. Some projects are cross-platform, other are system-agnostic.
Linux
Family of linux operating systems.
mobile
A family of mobile operating systems. These systems have very low resource requirements, and require applications that do not need much computing power.
Windows
In most cases denotes a family of Windows NT systems: Windows XP, Windows Vista, Windows 7, Windows 8, and later.