diff --git a/src/wp-includes/pomo/translations.php b/src/wp-includes/pomo/translations.php
index a5534a8ea9..0793b296b7 100644
--- a/src/wp-includes/pomo/translations.php
+++ b/src/wp-includes/pomo/translations.php
@@ -249,6 +249,9 @@ if ( ! class_exists( 'Translations', false ) ) :
 		 * Adds parentheses to the inner parts of ternary operators in
 		 * plural expressions, because PHP evaluates ternary oerators from left to right
 		 *
+		 * @deprecated 6.5.0 Use the Plural_Forms class instead.
+		 * @see Plural_Forms
+		 *
 		 * @param string $expression the expression without parentheses
 		 * @return string the expression with parentheses added
 		 */