diff -r 3e78723ffef0 -r b731df137efb relpipe-data/specification.xml
--- a/relpipe-data/specification.xml	Fri Nov 30 17:10:58 2018 +0100
+++ b/relpipe-data/specification.xml	Fri Nov 30 17:13:21 2018 +0100
@@ -108,6 +108,11 @@
 		
 		<h3>relpipe-out-gui</h3>
 		
+		<p>
+			A tool that views relational data in a GUI window. Relations are displayed as panels with tables.
+			Particular implementation might offer also additional features like chart drawing or simple statistics (sum, max, min, avg, percentiles etc.)
+		</p>
+		
 		
 		<h3>relpipe-out-xml</h3>