diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 5593a52..9f44413 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2106,12 +2106,23 @@
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 /**
- * \brief          Set the maximum fragment length to emit and/or negotiate
- *                 (Default: MBEDTLS_SSL_MAX_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           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().
  *
  * \param conf     SSL configuration
  * \param mfl_code Code for maximum fragment length (allowed values: