diff --git a/source b/source
index 2c209cb59e3..f50dc714819 100644
--- a/source
+++ b/source
@@ -101977,7 +101977,7 @@ dictionary <dfn>StorageEventInit</dfn> : <span>EventInit</span> {
    <dt>U+003D EQUALS SIGN (=)</dt>
    <dd>Switch to the <span>before attribute value state</span>.</dd>
 
-   <dt><span>ASCII lower alpha</span></dt>
+   <dt><span>ASCII upper alpha</span></dt>
    <dd>Append the lowercase version of the <span>current input character</span> (add 0x0020 to the
    character's code point) to the current attribute's name.</dd>