[Site Editor]: Update single default template copy

lib/compat/wordpress-6.1/block-template-utils.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * Temporary compatibility shims for features present in Gutenberg.
+ * This file should be removed when WordPress 6.1.0 becomes the lowest
+ * supported version by this plugin.
+ *
+ * @package gutenberg
+ */
+
+/**
+ * Updates the list of default template types, containing their
+ * localized titles and descriptions.
+ *
+ * We will only need to update `get_default_block_template_types` function.
+ *
+ * @param array $default_template_types The default template types.
+ *
+ * @return array The default template types.
+ */
+function gutenberg_get_default_block_template_types( $default_template_types ) {
+	if ( isset( $default_template_types['single'] ) ) {
+		$default_template_types['single'] = array(
+			'title'       => _x( 'Single', 'Template name', 'gutenberg' ),
+			'description' => __( 'The default template for displaying any single post or attachment.', 'gutenberg' ),
+		);
+	}
+	return $default_template_types;
+}
+add_filter( 'default_template_types', 'gutenberg_get_default_block_template_types', 10, 2 );

lib/load.php

@@ -126,6 +126,7 @@ function gutenberg_is_experiment_enabled( $name ) {
 require __DIR__ . '/compat/wordpress-6.1/get-global-styles-and-settings.php';
 require __DIR__ . '/compat/wordpress-6.1/script-loader.php';
 require __DIR__ . '/compat/wordpress-6.1/class-wp-theme-json-6-1.php';
+require __DIR__ . '/compat/wordpress-6.1/block-template-utils.php';
 
 // Experimental features.
 remove_action( 'plugins_loaded', '_wp_theme_json_webfonts_handler' ); // Turns off WP 6.0's stopgap handler for Webfonts API.