diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index dfe642ab82..3c83c00dc3 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -397,12 +397,13 @@ function strip_core_block_namespace( $block_name = null ) {
  *
  * @since 5.3.1
  *
- * @param string $block_name       Block name.
- * @param array  $block_attributes Block attributes.
- * @param string $block_content    Block save content.
+ * @param string|null $block_name       Block name. Null if the block name is unknown,
+ *                                      e.g. Classic blocks have their name set to null.
+ * @param array       $block_attributes Block attributes.
+ * @param string      $block_content    Block save content.
  * @return string Comment-delimited block content.
  */
-function get_comment_delimited_block_content( $block_name = null, $block_attributes, $block_content ) {
+function get_comment_delimited_block_content( $block_name, $block_attributes, $block_content ) {
 	if ( is_null( $block_name ) ) {
 		return $block_content;
 	}
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 863268c7bd..8d8e5001e2 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -830,14 +830,16 @@ function wp_extract_urls( $content ) {
  * @since 1.5.0
  * @since 5.3.0 The `$content` parameter was made optional, and the `$post` parameter was
  *              updated to accept a post ID or a WP_Post object.
+ * @since 5.6.0 The `$content` parameter is no longer optional, but passing `null` to skip it
+ *              is still supported.
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
- * @param string      $content Post content. If `null`, the `post_content` field from `$post` is used.
+ * @param string|null $content Post content. If `null`, the `post_content` field from `$post` is used.
  * @param int|WP_Post $post    Post ID or post object.
  * @return null|bool Returns false if post is not found.
  */
-function do_enclose( $content = null, $post ) {
+function do_enclose( $content, $post ) {
 	global $wpdb;
 
 	// @todo Tidy this code and make the debug code optional.
diff --git a/wp-includes/nav-menu.php b/wp-includes/nav-menu.php
index 53d4a15d0e..220f250e0b 100644
--- a/wp-includes/nav-menu.php
+++ b/wp-includes/nav-menu.php
@@ -1054,11 +1054,11 @@ function _wp_delete_post_menu_item( $object_id = 0 ) {
  * @since 3.0.0
  * @access private
  *
- * @param int    $object_id Optional. The ID of the original object being trashed. Default 0.
+ * @param int    $object_id The ID of the original object being trashed.
  * @param int    $tt_id     Term taxonomy ID. Unused.
  * @param string $taxonomy  Taxonomy slug.
  */
-function _wp_delete_tax_menu_item( $object_id = 0, $tt_id, $taxonomy ) {
+function _wp_delete_tax_menu_item( $object_id, $tt_id, $taxonomy ) {
 	$object_id = (int) $object_id;
 
 	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'taxonomy', $taxonomy );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ea58867014..51adf874db 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-48793';
+$wp_version = '5.6-alpha-48794';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.