Ticket #46124: 46124.2.patch

src/wp-includes/theme.php

@@ -1108 +1108 @@
         $width  = absint( $header->width );
         $height = absint( $header->height );
 
+        if ( ! empty( $header->alt_text ) ) {
+                $image_alt = $header->alt_text;
+        } elseif ( ! empty( $header->attachment_id ) ) {
+                $image_alt = get_post_meta( $header->attachment_id, '_wp_attachment_image_alt', true );
+        } else {
+                $image_alt = "";
+        }
+
         $attr = wp_parse_args(
                 $attr,
                 array(
@@ -1114 +1122 @@
                         'src'    => $header->url,
                         'width'  => $width,
                         'height' => $height,
-                        'alt'    => get_bloginfo( 'name' ),
+                        'alt'    => $image_alt,
                 )
         );
 
@@ -1356 +1364 @@
                 'width'         => get_theme_support( 'custom-header', 'width' ),
                 'height'        => get_theme_support( 'custom-header', 'height' ),
                 'video'         => get_theme_support( 'custom-header', 'video' ),
+                'alt_text'      => '',
         );
         return (object) wp_parse_args( $data, $default );
 }