diff --git a/docs/OpenTypeFeatureFileSpecification.md b/docs/OpenTypeFeatureFileSpecification.md
index ff5fd5b0a..7c5ef38e3 100644
--- a/docs/OpenTypeFeatureFileSpecification.md
+++ b/docs/OpenTypeFeatureFileSpecification.md
@@ -3350,7 +3350,7 @@ For example:
 table hhea {
     CaretOffset -50;
     Ascender 800;
-    Descender 200;
+    Descender -200; # Note that Descender is negative for descent below the baseline.
     LineGap 200;
 } hhea;
 ```