diff --git a/tests/opt-testcases/tls13-kex-modes.sh b/tests/opt-testcases/tls13-kex-modes.sh
old mode 100755
new mode 100644
index 782bda2..155149f
--- a/tests/opt-testcases/tls13-kex-modes.sh
+++ b/tests/opt-testcases/tls13-kex-modes.sh
@@ -1,14 +1,12 @@
-#!/bin/sh
-
-# tls13-kex-modes.sh
-#
-# Copyright The Mbed TLS Contributors
-# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
-#
+# Systematic testing of TLS 1.3 key exchange modes.
 
 # DO NOT ADD NEW TEST CASES INTO THIS FILE. The left cases will be generated by
 # scripts in future(#6280)
 
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+#
+
 requires_gnutls_tls1_3
 requires_all_configs_enabled MBEDTLS_SSL_PROTO_TLS1_3 MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE MBEDTLS_SSL_SRV_C MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED