The script file /etc/X11/xdm/Xsession refers to file /usr/X11R6/lib/X11/xinit/.Xmodmap , but only /usr/X11R6/lib/X11/xinit/Xmodmap exists there. related rpm : XFree86-3.3.5-3
added in latest release: looks at Xmodmap in addition to .Xmodmap. .Xmodmap is being maintained for backwards compatibility.