PfUG v.2.2: Building in Pfhorte!
is apparently about the Marathon 1 version of that mapping app, but it does have some documentation.
If you step in a Glue Trigger polygon, it makes a signal that activates monsters, a signal that propagates from polygon to polygon. But that signal will be stopped by SuperGlue polygons.
Likewise, a Glue polygon will stop the signals that activating monsters produce.
Marathon 2/oo uses different polygon types to do those effects, like "zone border".