diff --git a/urls.py b/urls.py
index 6b79ab5..f75975b 100644
--- a/urls.py
+++ b/urls.py
@@ -55,6 +55,11 @@ todo = '''
 # not yet restored all the functions. Some may have never been fully implemented in
 # the first place and what they were intended to provide is obscure.
 
+
+# WHen running on the server, apache intercepts all teh /expofiles/ files so troggle never sees them,
+# so the "content type" is set by whatever apache thinks it should be. Which means .gpx files
+# get treated as XML and the web browser fails to do anything usefull
+
 if settings.EXPOFILESREMOTE:
     expofilesurls = [
         path('<path:filepath>',    expofiles_redirect, name="expofiles_redirect"), # to http://expo.survex.com/expofiles