can just concacenate the two without worrying about it leaking back out in a
later write.
+> Implementing this is in progress, in the `hiddenannex` branch.
+>
+> Got the separate journal mostly working. No separate index yet.
+> No way to configure what repo is hidden yet. --[[Joey]]
+>
+> Implementation notes:
+>
+> * CmdLine.Seek precaches git-annex branch
+> location logs, but that does not include private ones. Since they're
+> cached, the private ones don't get read. Result is eg, whereis finds no
+> copies. Either need to disable CmdLine.Seek precaching when there's
+> hidden repos, or could make the cache indicate it's only of public
+> info, so private info still gets read.
+> * CmdLine.Seek contains a LsTreeRecursive over the branch to handle
+> --all, and again that won't see private information, including even
+> annexed files that are only present in the hidden repo.
+> * (And I wonder, don't both the caches above already miss things in
+> the journal?)
+> * Any other direct accesses of the branch, not going through
+> Annex.Branch, also need to be fixed (and may be missing journal files
+> already?) Command.ImportFeed.knownItems is one. Command.Log behavior
+> needs to be investigated, may be ok. And Logs.Web.withKnownUrls is another.
+
## networks of hidden repos
There are a lot of complications involving using hidden repos as remotes.