diff --git a/Types/Remote.hs b/Types/Remote.hs
index 1c9920c0c4..4c2577aa21 100644
--- a/Types/Remote.hs
+++ b/Types/Remote.hs
@@ -89,6 +89,8 @@ data RemoteA a = Remote
 	-- Remotes have a use cost; higher is more expensive
 	, cost :: Cost
 	-- Transfers a key's contents from disk to the remote.
+	-- The optional OsPath is the location of the key's object file.
+	-- When not provided, uses the annex object file.
 	-- The key should not appear to be present on the remote until
 	-- all of its contents have been transferred.
 	-- Throws exception on failure.