Extended Window Manager Hints, aka NetWM or Net WM, is an X Window System standard for window managers. It defines various interactions between window managers, utilities, and applications, all part of an entire desktop environment. It builds on the functionality of the Inter-Client Communication Conventions Manual (ICCCM).
List of window managers that support Extended Window Manager Hints
Tiling and dynamic window managers
Stacking window managers
Other window managers
Notes and references