diff --git a/library/bignum_core.c b/library/bignum_core.c
index ed0c3d0d72c4..430f6627a3aa 100644
--- a/library/bignum_core.c
+++ b/library/bignum_core.c
@@ -550,6 +550,8 @@ int mbedtls_mpi_core_get_mont_r2_unsafe( mbedtls_mpi *X,
 
 /* BEGIN MERGE SLOT 3 */
 
+// Use slot 3
+
 /* END MERGE SLOT 3 */
 
 /* BEGIN MERGE SLOT 4 */