xkill is a utility for forcing the X server to close connections to clients. This program is very dangerous, but is useful for aborting programs that have displayed undesired windows on a user's screen. All questions regarding this software should be directed at the Xorg mailing list: https://lists.x.org/mailman/listinfo/xorg The master development code repository can be found at: https://gitlab.freedesktop.org/xorg/app/xkill Please submit bug reports and requests to merge patches there. For patch submission instructions, see: https://www.x.org/wiki/Development/Documentation/SubmittingPatches