diff --git a/dnstap/unbound-dnstap-socket.c b/dnstap/unbound-dnstap-socket.c
index d854ef435..217df1c87 100644
--- a/dnstap/unbound-dnstap-socket.c
+++ b/dnstap/unbound-dnstap-socket.c
@@ -65,7 +65,7 @@
 #include "dnstap/dnstap.pb-c.h"
 #include "util/config_file.h"
 
-#define DNSTAP_CONTENT_TYPE             "protobuf:dnstap.Dnstap"
+/** listen backlog on TCP connections for dnstap logs */
 #define LISTEN_BACKLOG 16
 
 /** usage information for streamtcp */