Issue Report: if $XDG_DESKTOP_DIR is not set steam assumes $HOME/Desktop to be present
As the title says: if $XDG_DESKTOP_DIR is not set, then the initial /usr/bin/steam script assumes $HOME/Desktop to be present.
It will then try to copy /usr/share/applications/steam.desktop to $HOME/Desktop. Should $HOME/Desktop not be present then instead of the desired effect, a .desktop file will be created with the name $HOME/Desktop which is obviously wrong.
The following chmod line will fail as well as it tries to chmod $DESKTOP_DIR/$STEAMPACKAGE.desktop which does not exist at this point.