diff --git a/Use-Cases.md b/Use-Cases.md
index 604aa80..80dce70 100644
--- a/Use-Cases.md
+++ b/Use-Cases.md
@@ -36,7 +36,7 @@ This alternative can be implemented if the layer knows the map projection.  The
 
 _Questions from Eric:_
 
-How do we know that the transform's source projection is EPSG:4326? It's not specified anywhere in the application code.
+How do we know that the transform's source projection is EPSG:4326? It's not specified anywhere in the application code. Is the user/external projection EPSG:4326 by default?
 
 Why does the layer need to know about the map/view projection for implementing this? The layer renderer knows about the map/view projection, so it can be the one providing the projection.