diff --git a/backport-changelog/6.6/6841.md b/backport-changelog/6.6/6841.md
new file mode 100644
index 00000000000000..36e715c48f52e0
--- /dev/null
+++ b/backport-changelog/6.6/6841.md
@@ -0,0 +1,3 @@
+https://github.com/WordPress/wordpress-develop/pull/6841
+
+* https://github.com/WordPress/gutenberg/pull/62598
diff --git a/packages/block-serialization-default-parser/class-wp-block-parser-frame.php b/packages/block-serialization-default-parser/class-wp-block-parser-frame.php
index 15938dea389aad..6ab5dd3087dfb6 100644
--- a/packages/block-serialization-default-parser/class-wp-block-parser-frame.php
+++ b/packages/block-serialization-default-parser/class-wp-block-parser-frame.php
@@ -65,8 +65,9 @@ class WP_Block_Parser_Frame {
 	 * @param WP_Block_Parser_Block $block              Full or partial block.
 	 * @param int                   $token_start        Byte offset into document for start of parse token.
 	 * @param int                   $token_length       Byte length of entire parse token string.
-	 * @param int                   $prev_offset        Byte offset into document for after parse token ends.
-	 * @param int                   $leading_html_start Byte offset into document where leading HTML before token starts.
+	 * @param int|null              $prev_offset        Optional. Byte offset into document for after parse token ends. Default null.
+	 * @param int|null              $leading_html_start Optional. Byte offset into document where leading HTML before token starts.
+	 *                                                  Default null.
 	 */
 	public function __construct( $block, $token_start, $token_length, $prev_offset = null, $leading_html_start = null ) {
 		$this->block              = $block;