@@ -1912,6 +1912,35 @@ public function filter_wp_kses_object_added_in_html_filter( $tags, $context ) {
 		return $tags;
 	}
 
+	/**
+	 * Ensures that `wp_kses()` preserves various kinds of HTML comments, both valid and invalid.
+	 *
+	 * @ticket 61009
+	 *
+	 * @param string $html_comment    HTML containing a comment; must not be a valid comment
+	 *                                but must be syntax which a browser interprets as a comment.
+	 * @param string $expected_output How `wp_kses()` ought to transform the comment.
+	 */
+	public function wp_kses_preserves_html_comments( $html_comment, $expected_output ) {
+		$this->assertSame(
+			$expected_output,
+			wp_kses( $html_comment, array() ),
+			'Failed to properly preserve HTML comment.'
+		);
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array[].
+	 */
+	public static function data_html_containing_various_kinds_of_html_comments() {
+		return array(
+			'Normative HTML comment'            => array( 'before<!-- this is a comment -->after', 'before<!-- this is a comment -->after' ),
+			'Closing tag with invalid tag name' => array( 'before<//not a tag>after', 'before<//not a tag>after' ),
+		);
+	}
+
 	/**
 	 * Test that attributes with a list of allowed values are filtered correctly.
 	 *