Looked over bugs filed about v6 mode and did some triage and analysis.
[[todo/smudge]] has the details.

This led to changing what's done by `git add` and `git commit file` when
annex.largefiles is not configured. Rather than behaving like `git annex
add` and always storing the file in the annex, it will store it in the
annex if the old version was annexed, and in git if the old version was
stored in git. This avoids accidental conversions.

It might make sense to have `git annex add` also do this, even in v5
repositories, but I want to concentrate on v6 for now, and also don't
think that `git add` and `git annex add` necessarily need to behave
identically in v6 mode. While using `git commit -a` doesn't imply
anything about whether you want the file in git or the annex,
using `git-annex add` seems to imply they you want it in
the annex, unless you've gone out of your way to configure otherwise.

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Also did some design work on supporting versioned S3 buckets with
`git-annex export`.

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This work is supported by the NSF-funded DataLad project.