diff --git a/spec/abstractops.html b/spec/abstractops.html
index 2b66bf7cfc..4e8ab104be 100644
--- a/spec/abstractops.html
+++ b/spec/abstractops.html
@@ -1117,7 +1117,7 @@ <h1>ISO 8601 grammar</h1>
 
       TZChar[Legacy] :
           TZLeadingChar
-          `_`
+          `-`
           [+Legacy] `+`
           [+Legacy] DecimalDigit