/usr/share/doc/sysprofile/examples/etc/X11/wdm/Xsession.sample is in sysprofile 0.3.9.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 | #!/bin/sh
# This is an Xsession wrapper for use with wdm to take care of the
# handling of the 'NoChange' window manager selection option.
# Run /etc/sysprofile before invoking /etc/X11/Xsession
if [ -f /etc/sysprofile ]; then . /etc/sysprofile; fi
if [ $# -eq 1 ] ; then echo $1 >$HOME/.wm_style ; fi
shift ; exec /etc/X11/Xsession `cat $HOME/.wm_style` $@
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