diff --git a/src/Tahoe/Download.hs b/src/Tahoe/Download.hs
index a9f31a456c206effa78a521c0e02f467daa05999..5b25fd32880e3e5bb6d166f1515c8e56a2d58e4f 100644
--- a/src/Tahoe/Download.hs
+++ b/src/Tahoe/Download.hs
@@ -300,6 +300,10 @@ makeServer
                 pure . Right $ wrapGreatBlackSwamp manager host realPort
 makeServer _ = pure . Left $ AnnouncementStructureUnmatched
 
+-- Parameterize readImmutableShare and getImmutableShareNumbers to
+-- wrapGreatBlackSwamp, then use it for both mutables and immutables.  Then
+-- use the same download function for both!
+
 {- | Create a StorageServer that will speak Great Black Swamp using the given
  manager to the server at the given host/port.
 -}