diff --git a/lib/extract_entity.xsl b/lib/extract_entity.xsl
index fa9fc07..6a25135 100644
--- a/lib/extract_entity.xsl
+++ b/lib/extract_entity.xsl
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-	Copyright 2016 Internet2
+	Copyright 2016-2017 Internet2
 
 	Licensed under the Apache License, Version 2.0 (the "License");
 	you may not use this file except in compliance with the License.
@@ -18,7 +18,11 @@
 	extract_entity.xsl
 	
 	An XSL transform that takes a SAML V2.0 metadata file and 
-	extracts a single entity descriptor.
+	a stringparam (entityID) on the command line. It then 
+	extracts the entity descriptor with the given entityID
+	from the aggregate.
+	
+	See md_tools.sh for a use of this stylesheet.
 -->
 <xsl:stylesheet version="1.0"
 	xmlns:xsl="http://www.w3.org/1999/XSL/Transform"