diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 42fffbf..a7bfd7b 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1884,8 +1884,16 @@
      * User settings
      */
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
-    char *MBEDTLS_PRIVATE(hostname);             /*!< expected peer CN for verification
-                                                    (and SNI if available)                 */
+    /** Expected peer CN for verification.
+     *
+     * Also used on clients for SNI,
+     * and for TLS 1.3 session resumption using tickets.
+     *
+     * If this is \p NULL, the peer name verification is skipped,
+     * the server_name extension is not sent, and the server name is ignored
+     * in TLS 1.3 session resumption using tickets.
+     */
+    char *MBEDTLS_PRIVATE(hostname);
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_SSL_ALPN)