Previous discussion which touched upon it was 7 years ago (unless I missed some) where part of the response was

I don't see the benefit to justify this work. git annex add is entirely predictable; it's very similar to git add. Which itself lacks a dry-run option.

Oh well:

$> git add --help | grep -e '-n, --dry' -A1
       -n, --dry-run
           Don’t actually add the file(s), just show if they exist and/or will be ignored.

and users submit requests against DataLad to be able to discover what file would go to git and which to git-annex. Also would be useful to know if to git-annex -- would it be locked or unlocked? Someone else might even want to discover what would be the annex key if it would go into annex, but so far I do not think it is within our desired use-case and it might be too lengthy to compute the key checksum etc.

As for

And like git add, you can certianly undo the effects of git annex add.

well -- unless there was a version staged already you don't want to loose etc.

done joey