diff --git a/wp-includes/blocks/list.php b/wp-includes/blocks/list.php
new file mode 100644
index 0000000000..1bffd81324
--- /dev/null
+++ b/wp-includes/blocks/list.php
@@ -0,0 +1,54 @@
+ is transformed to
.
+ *
+ * @since 6.6.0
+ *
+ * @see https://github.com/WordPress/gutenberg/issues/12420
+ *
+ * @param array $attributes Attributes of the block being rendered.
+ * @param string $content Content of the block being rendered.
+ *
+ * @return string The content of the block being rendered.
+ */
+function block_core_list_render( $attributes, $content ) {
+ if ( ! $content ) {
+ return $content;
+ }
+
+ $processor = new WP_HTML_Tag_Processor( $content );
+
+ $list_tags = array( 'OL', 'UL' );
+ while ( $processor->next_tag() ) {
+ if ( in_array( $processor->get_tag(), $list_tags, true ) ) {
+ $processor->add_class( 'wp-block-list' );
+ break;
+ }
+ }
+
+ return $processor->get_updated_html();
+}
+
+/**
+ * Registers the `core/list` block on server.
+ *
+ * @since 6.6.0
+ */
+function register_block_core_list() {
+ register_block_type_from_metadata(
+ __DIR__ . '/list',
+ array(
+ 'render_callback' => 'block_core_list_render',
+ )
+ );
+}
+
+add_action( 'init', 'register_block_core_list' );
diff --git a/wp-includes/blocks/media-text.php b/wp-includes/blocks/media-text.php
new file mode 100644
index 0000000000..f828aed645
--- /dev/null
+++ b/wp-includes/blocks/media-text.php
@@ -0,0 +1,71 @@
+';
+ $content = preg_replace( '/