diff --git a/src/wp-includes/class-wp-theme.php b/src/wp-includes/class-wp-theme.php
index 511699adce..c18896ec17 100644
--- a/src/wp-includes/class-wp-theme.php
+++ b/src/wp-includes/class-wp-theme.php
@@ -179,6 +179,7 @@ final class WP_Theme implements ArrayAccess {
 
 		// Initialize caching on first run.
 		if ( ! isset( self::$persistently_cache ) ) {
+			/** This action is documented in wp-includes/theme.php */
 			self::$persistently_cache = apply_filters( 'wp_cache_themes_persistently', false, 'WP_Theme' );
 			if ( self::$persistently_cache ) {
 				wp_cache_add_global_groups( 'themes' );
@@ -1086,6 +1087,13 @@ final class WP_Theme implements ArrayAccess {
 	 * @return array Array of stylesheet names.
 	 */
 	public static function get_allowed( $blog_id = null ) {
+		/**
+		 * Filter the array of themes allowed on the site or network.
+		 *
+		 * @since MU
+		 *
+		 * @param array $allowed_themes An array of theme stylesheet names.
+		 */
 		$network = (array) apply_filters( 'allowed_themes', self::get_allowed_on_network() );
 		return $network + self::get_allowed_on_site( $blog_id );
 	}