Ticket #33123: theme-mod-default.patch

theme.php

@@ -951 +951 @@
         if ( is_string( $default ) )
                 $default = sprintf( $default, get_template_directory_uri(), get_stylesheet_directory_uri() );
 
+        /**
+         * Filter the theme modification default value.
+         *
+         * The dynamic portion of the hook name, `$name`, refers to
+         * the key name of the modification array. For example,
+         * 'header_textcolor', 'header_image', and so on depending
+         * on the theme options.
+         *
+         * @since 4.3.0
+         *
+         * @param string $default The default value of the current theme modification.
+         */
+        $default = apply_filters( "theme_mod_{$name}_default", $default );
+
         /** This filter is documented in wp-includes/theme.php */
         return apply_filters( "theme_mod_{$name}", $default );
 }