diff --git a/src/backend/main/main.c b/src/backend/main/main.c
index a9edbfd4a4..5c818c7691 100644
--- a/src/backend/main/main.c
+++ b/src/backend/main/main.c
@@ -198,6 +198,7 @@ main(int argc, char *argv[])
 	pgwin32_signal_initialize();
 #endif
 
+	/* Bootstrap mode for initdb */
 	if (argc > 1 && strcmp(argv[1], "--boot") == 0)
 		AuxiliaryProcessMain(argc, argv);	/* does not return */
 	else if (argc > 1 && strcmp(argv[1], "--describe-config") == 0)