diff --git a/doc/04-schema.md b/doc/04-schema.md
index 853444d8f..5886608e6 100644
--- a/doc/04-schema.md
+++ b/doc/04-schema.md
@@ -165,7 +165,7 @@ An example:
 
 Optional, but highly recommended.
 
-### Link types
+### Link types <span>(require, recommend, suggest, replace, provide)</span>
 
 Each of these takes an object which maps package names to version constraints.