diff --git a/wp-includes/deprecated.php b/wp-includes/deprecated.php
index 3b4dc8d26..db137793e 100644
--- a/wp-includes/deprecated.php
+++ b/wp-includes/deprecated.php
@@ -57,3 +57,30 @@ function wp_service_worker_json_encode( $data ) {
 	_deprecated_function( __FUNCTION__, '0.6', 'wp_json_encode()' );
 	return wp_json_encode( $data, 128 | 64 /* JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES */ );
 }
+
+/**
+ * Disables concatenating scripts to leverage caching the assets via Service Worker instead.
+ *
+ * @deprecated 0.7 No longer used.
+ */
+function wp_disable_script_concatenation() {
+	_deprecated_function( __FUNCTION__, '0.7' );
+
+	global $concatenate_scripts;
+
+	/*
+	 * This cookie is set when the service worker registers successfully, avoiding unnecessary result
+	 * for browsers that don't support service workers. Note that concatenation only applies in the admin,
+	 * for authenticated users without full-page caching.
+	 */
+	if ( isset( $_COOKIE['wordpress_sw_installed'] ) ) {
+		$concatenate_scripts = false; // phpcs:ignore WordPress.WP.GlobalVariablesOverride.Prohibited
+	}
+
+	// phpcs:disable
+	// @todo This is just here for debugging purposes.
+	if ( isset( $_GET['wp_concatenate_scripts'] ) ) {
+		$concatenate_scripts = rest_sanitize_boolean( $_GET['wp_concatenate_scripts'] );
+	}
+	// phpcs:enable
+}