That's the only (obvious) thing I spotted going through the scripts to determine what's actually getting installed and where. It's more of a login agnostic feature. The way I understand it, if a user boots to a command line and uses "startx" when they want to start an X-session, the $HOME/.xinitrc is read and the window manager of choice is started. If a newer login manager like lightdm or lxdm (gdm, kdm?) is used, the $HOME/.xsessionrc is read and the window manager started along with the other features of the login manager. By calling the $HOME/.xinitrc in $HOME/.xsessionrc a user only needs the one file and is consistent when starting an X-session. Use to be a distro would create a symlink to accomplish that, but that appears to have fallen by the wayside.