diff --git a/docs/revsets.md b/docs/revsets.md
index 4a0721aa14..10362c587e 100644
--- a/docs/revsets.md
+++ b/docs/revsets.md
@@ -78,6 +78,9 @@ only symbols.
 You can use parentheses to control evaluation order, such as `(x & y) | z` or
 `x & (y | z)`.
 
+<!-- The following format will be understood by the web site generator, and will
+ generate a folded section that can be unfolded at will. -->
+
 ??? examples
 
     Given this history: