Installing q will change the operation of the Backspace key in an xterm from
sending BS to sending DEL (the same as in a VT console).
The install process updates /etc/X11/app-defaults/XTerm to achieve this.
The change will not be visible until X is restarted. Before that, the user
can un-tick "Backarrow Key (BS/DEL)" in the main xterm menu (Ctl-mb1).