diff --git a/Packaging.md b/Packaging.md
index 4d6493c..5c1b263 100644
--- a/Packaging.md
+++ b/Packaging.md
@@ -26,7 +26,7 @@ For libraries that Tahoe uses, we have these desiderata:
  * Use it as it is packaged by upstream. That is: we prefer to get a copy of
    the source code of the package as upstream prefers to distribute such
    source code, rather than by pulling from their revision control tool or so
-   on.
+   on.  (But we strongly prefer source packages to binary.)
 
  * The user doesn't have to manually resolve any conflicts (this means that
    we either have to automatically use a 3rd-party library if it is already