diff --git a/src/wp-includes/class-wp-block-parser-block.php b/src/wp-includes/class-wp-block-parser-block.php
index 97dd687c1ffe1..8fbeedd14bec9 100644
--- a/src/wp-includes/class-wp-block-parser-block.php
+++ b/src/wp-includes/class-wp-block-parser-block.php
@@ -14,12 +14,12 @@
  */
 class WP_Block_Parser_Block {
 	/**
-	 * Name of block
+	 * Name of block, or `null` when the block is top-level freeform HTML content.
 	 *
 	 * @example "core/paragraph"
 	 *
 	 * @since 5.0.0
-	 * @var string
+	 * @var string|null
 	 */
 	public $blockName; // phpcs:ignore WordPress.NamingConventions.ValidVariableName
 
@@ -74,11 +74,11 @@ class WP_Block_Parser_Block {
 	 *
 	 * @since 5.0.0
 	 *
-	 * @param string $name          Name of block.
-	 * @param array  $attrs         Optional set of attributes from block comment delimiters.
-	 * @param array  $inner_blocks  List of inner blocks (of this same class).
-	 * @param string $inner_html    Resultant HTML from inside block comment delimiters after removing inner blocks.
-	 * @param array  $inner_content List of string fragments and null markers where inner blocks were found.
+	 * @param string|null $name          Name of block, or `null` for freeform HTML content.
+	 * @param array       $attrs         Optional set of attributes from block comment delimiters.
+	 * @param array       $inner_blocks  List of inner blocks (of this same class).
+	 * @param string      $inner_html    Resultant HTML from inside block comment delimiters after removing inner blocks.
+	 * @param array       $inner_content List of string fragments and null markers where inner blocks were found.
 	 */
 	public function __construct( $name, $attrs, $inner_blocks, $inner_html, $inner_content ) {
 		$this->blockName    = $name;          // phpcs:ignore WordPress.NamingConventions.ValidVariableName
diff --git a/src/wp-includes/class-wp-block-parser.php b/src/wp-includes/class-wp-block-parser.php
index 06342fc5acb64..7671442a446e3 100644
--- a/src/wp-includes/class-wp-block-parser.php
+++ b/src/wp-includes/class-wp-block-parser.php
@@ -35,6 +35,8 @@ class WP_Block_Parser {
 	/**
 	 * List of parsed blocks
 	 *
+	 * See WP_Block_Parser_Block for the structure of each block.
+	 *
 	 * @since 5.0.0
 	 * @var array[]
 	 */
@@ -68,7 +70,22 @@ class WP_Block_Parser {
 	 * @since 5.0.0
 	 *
 	 * @param string $document Input document being parsed.
-	 * @return array[]
+	 * @return array[] {
+	 *     Array of block structures.
+	 *
+	 *     @type array ...$0 {
+	 *         An associative array of a single parsed block object. See WP_Block_Parser_Block.
+	 *
+	 *         @type string|null $blockName    Name of block, or `null` when the block is
+	 *                                         top-level freeform HTML content.
+	 *         @type array       $attrs        Attributes from block comment delimiters.
+	 *         @type array[]     $innerBlocks  List of inner blocks. An array of arrays that
+	 *                                         have the same structure as this one.
+	 *         @type string      $innerHTML    HTML from inside block comment delimiters.
+	 *         @type array       $innerContent List of string fragments and null markers where
+	 *                                         inner blocks were found.
+	 *     }
+	 * }
 	 */
 	public function parse( $document ) {
 		$this->document = $document;
diff --git a/tests/phpstan/baselines/argument.type.neon b/tests/phpstan/baselines/argument.type.neon
index 4441460ac0799..1e3390226e752 100644
--- a/tests/phpstan/baselines/argument.type.neon
+++ b/tests/phpstan/baselines/argument.type.neon
@@ -673,11 +673,6 @@ parameters:
 			identifier: argument.type
 			count: 1
 			path: ../../../src/wp-includes/capabilities.php
-		-
-			message: '#^Parameter \#1 \$name of class WP_Block_Parser_Block constructor expects string, null given\.$#'
-			identifier: argument.type
-			count: 1
-			path: ../../../src/wp-includes/class-wp-block-parser.php
 		-
 			message: '#^Parameter \#1 \$ajax_message of method WP_Customize_Manager\:\:wp_die\(\) expects string\|WP_Error, int given\.$#'
 			identifier: argument.type