diff --git a/doc/developer.md b/doc/developer.md
index eb1f66b6315..f1b7e64ca9b 100644
--- a/doc/developer.md
+++ b/doc/developer.md
@@ -128,4 +128,6 @@ than that, perhaps toss in a comment.
 
 Prefer `std::ostringstream` and so on to `sprintf` and so on.
 
+`#pragma once`, while not [really standard](https://en.wikipedia.org/wiki/Pragma_once), is used in 
+most of the code, so we are continuing to use it rather than ifdef guards.