diff --git a/doc/todo/external_special_remote_not_used_concurrently_with_-J.mdwn b/doc/todo/external_special_remote_not_used_concurrently_with_-J.mdwn
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+When using an external special remote with -Jn, multiple transfers do not
+happen concurrently to the remote. A single process is
+started for the external special remote, and there's locking to only let
+one request be made of it at a time.
+
+This should not be hard to make to use a pool of Externals, starting up a
+new one if the pool is empty or all in use. --[[Joey]]
+
+[[users/yoh]] may want this for datalad?