diff --git a/include/curl/curl.h b/include/curl/curl.h
index 898cbda839..78901591c1 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -159,7 +159,7 @@ typedef enum {
   CURLSSLBACKEND_NONE = 0,
   CURLSSLBACKEND_OPENSSL = 1,
   CURLSSLBACKEND_GNUTLS = 2,
-  CURLSSLBACKEND_NSS = 3,
+  CURLSSLBACKEND_NSS                    CURL_DEPRECATED(8.3.0, "") = 3,
   CURLSSLBACKEND_OBSOLETE4 = 4,  /* Was QSOSSL. */
   CURLSSLBACKEND_GSKIT                  CURL_DEPRECATED(8.3.0, "") = 5,
   CURLSSLBACKEND_POLARSSL               CURL_DEPRECATED(7.69.0, "") = 6,