diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a973d7150..62a38b71c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -133,6 +133,12 @@ are optional and will not have any effect for now.
 @structure
 ```
 
+#### Variables
+```
+@variable
+  builtin
+```
+
 #### Text
 
 Mainly for markup languages.