Reword ssl_conf_max_frag_len documentation for clarity
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 8106bb4..d31f6cd 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2532,22 +2532,28 @@
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 /**
- * \brief          Set the maximum fragment length to emit and/or negotiate
- *                 (Default: the smaller of MBEDTLS_SSL_IN_CONTENT_LEN and
- *                 MBEDTLS_SSL_OUT_CONTENT_LEN, usually 2^14 bytes)
+ * \brief          Set the maximum fragment length to emit and/or negotiate.
+ *                 (Typical: the smaller of #MBEDTLS_SSL_IN_CONTENT_LEN and
+ *                 #MBEDTLS_SSL_OUT_CONTENT_LEN, usually `2^14` bytes)
  *                 (Server: set maximum fragment length to emit,
- *                 usually negotiated by the client during handshake
+ *                 usually negotiated by the client during handshake)
  *                 (Client: set maximum fragment length to emit *and*
  *                 negotiate with the server during handshake)
+ *                 (Default: #MBEDTLS_SSL_MAX_FRAG_LEN_NONE)
  *
- * \note           With TLS, this currently only affects ApplicationData (sent
- *                 with \c mbedtls_ssl_read()), not handshake messages.
- *                 With DTLS, this affects both ApplicationData and handshake.
+ * \note           On the client side, the maximum fragment length extension
+ *                 *will not* be used, unless the maximum fragment length has
+ *                 been set via this function to a value different than
+ *                 #MBEDTLS_SSL_MAX_FRAG_LEN_NONE.
  *
  * \note           This sets the maximum length for a record's payload,
  *                 excluding record overhead that will be added to it, see
  *                 \c mbedtls_ssl_get_record_expansion().
  *
+ * \note           With TLS, this currently only affects ApplicationData (sent
+ *                 with \c mbedtls_ssl_read()), not handshake messages.
+ *                 With DTLS, this affects both ApplicationData and handshake.
+ *
  * \note           For DTLS, it is also possible to set a limit for the total
  *                 size of daragrams passed to the transport layer, including
  *                 record overhead, see \c mbedtls_ssl_set_mtu().