diff --git a/libs/ardour/ardour/debug.h b/libs/ardour/ardour/debug.h
index cd96aba33a..7ba336d58a 100644
--- a/libs/ardour/ardour/debug.h
+++ b/libs/ardour/ardour/debug.h
@@ -95,6 +95,7 @@ namespace PBD {
 		LIBARDOUR_API extern DebugBits Push2;
 		LIBARDOUR_API extern DebugBits US2400;
 		LIBARDOUR_API extern DebugBits LaunchControlXL;
+		LIBARDOUR_API extern DebugBits BackendCallbacks;
 
 	}
 }
diff --git a/libs/ardour/debug.cc b/libs/ardour/debug.cc
index 403bb03263..9e60d581f2 100644
--- a/libs/ardour/debug.cc
+++ b/libs/ardour/debug.cc
@@ -91,3 +91,4 @@ PBD::DebugBits PBD::DEBUG::VCA = PBD::new_debug_bit ("vca");
 PBD::DebugBits PBD::DEBUG::Push2 = PBD::new_debug_bit ("push2");
 PBD::DebugBits PBD::DEBUG::US2400 = PBD::new_debug_bit ("us2400");
 PBD::DebugBits PBD::DEBUG::LaunchControlXL = PBD::new_debug_bit("launchcontrolxl");
+PBD::DebugBits PBD::DEBUG::BackendCallbacks = PBD::new_debug_bit("BackendCallbacks");