[[!comment format=mdwn
 username="Ilya_Shlyakhter"
 avatar="http://cdn.libravatar.org/avatar/1647044369aa7747829c38b9dcc84df0"
 subject="backends vs special remotes"
 date="2020-02-20T19:23:04Z"
 content="""
@annex2384 \"Backend which doesn't store files at all?\" -- are you sure you're thinking of backends and not of [[special_remotes]]?  Backends don't \"store files\", special remotes do.  Backends create keys identifying specific contents.

Not sure I fully understand your use case, but you could write an [[external special remote|special_remotes/external]] that, for a given git-annex key, stores \"the location of possible local copies of the file\" -- e.g. using `SETSTATE` or `SETURIPRESENT`.
"""]]