1 files changed, 11 insertions, 1 deletions

diff --git a/src/include/gnunet_nt_lib.h b/src/include/gnunet_nt_lib.h
index 18419a7b8..014b4fbe0 100644
--- a/src/include/gnunet_nt_lib.h
+++ b/src/include/gnunet_nt_lib.h
@@ -17,12 +17,20 @@
 
      SPDX-License-Identifier: AGPL3.0-or-later
  */
+
+#if !defined (__GNUNET_UTIL_LIB_H_INSIDE__)
+#error "Only <gnunet_util_lib.h> can be included directly."
+#endif
+
 /**
+ * @addtogroup Backbone
+ * @{
+ *
  * @file network type characterization
  * @author Christian Grothoff
  * @author Matthias Wachs
  *
- * @defgroup nt  network type characterization
+ * @defgroup nt  Network type characterization
  *
  * @{
  */
@@ -122,3 +130,5 @@ GNUNET_NT_scanner_done (struct GNUNET_NT_InterfaceScanner *is);
 #endif
 
 /** @} */  /* end of group */
+
+/** @} */  /* end of group addition to backbone */