Improve doc for Garmin-specific options in GPX writer.

diff --git a/gpsbabel/xmldoc/formats/options/gpx-garminextensions.xml b/gpsbabel/xmldoc/formats/options/gpx-garminextensions.xml
index 16b18197ec6e12fa6e58ab98663b2e3d335540a1..e49e344e521a099892c21b6c1eaa77e4dd808701 100644 (file)
--- a/gpsbabel/xmldoc/formats/options/gpx-garminextensions.xml
+++ b/gpsbabel/xmldoc/formats/options/gpx-garminextensions.xml
@@ -1,3 +1,10 @@
+<para>
+  Write Garmin-specific extensions, when such data is available, to the GPX.
+  Notably, depth, temperature, proximity, display color, ambient temperature,
+  heart rate, and cadence are read when they are available in the source data.
+  This data can, of course, only be read by GPX readers that know about the 
+  Garmin gpxtpx and gpxx extended namespaces.
+</para>
 <para>
 Implies <option>gpxver=1.1</option>
 </para>