diff --git a/doc/sandbox.mdwn b/doc/sandbox.mdwn
index cbef5394e..f6d8ac440 100644
--- a/doc/sandbox.mdwn
+++ b/doc/sandbox.mdwn
@@ -46,6 +46,7 @@ Bulleted list
 * [[different_name_for_a_WikiLink|ikiwiki/WikiLink]]
 * <http://www.gnu.org/>
 * [GNU](http://www.gnu.org/)
+* <file:///tmp/test.html>
 
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