The fvwm auto-raise module
FvwmAuto is spawned by fvwm, so no command line invocation will work. An appropriate invocation from fvwm looks like:
Module FvwmAuto 200
or, from a menu: Popup "Module-Popup"
Title "Modules" Module "GoodStuff" GoodStuff Module "NoClutter" FvwmClean Module "FvwmIdentify" FvwmIdent Module "Banner" FvwmBanner Module "Debug" FvwmDebug Module "SaveDesktop" FvwmSave Module "AutoRaise" FvwmAuto 200
EndPopup
The numeric argument is required. It specified how long a window must retain the keyboard input focus before it is raised. The delay is measured in milliseconds, and any integer 0 or greater is acceptable.
FvwmAuto just appeared one day, nobody knows how.