note about that list

it should really be NonEmpty but then we'd have to write a NonEmpty path
encoder, I guess

obelisk/common/src/Common/Route.hs

@@ -44,7 +44,8 @@ data FrontendRoute :: * -> * where
   FrontendRoute_MagicFolders :: FrontendRoute ()
 
   -- | Show the contents of some folder within a magic-folder (maybe the
-  -- root).
+  -- root).  The first element of the list identifies the magic-folder.  The
+  -- subsequent elements identify a folder contained by that magic-folder.
   FrontendRoute_FileBrowser :: FrontendRoute [Text]
 
 -- | Define the mapping between routes and URL paths & query parameters.  Be