[[!comment format=mdwn
 username="joey"
 subject="""comment 2"""
 date="2019-01-01T16:26:57Z"
 content="""
Obvious reason is that it's not something often used or that has had much
demand for being sped up. And in particular it's written as a call to
unannex each annexed file, and that runs `git rm --cached` once per file,
which can be slow.

But there are also non-obvious things that it may need to do that can be
slow. For example, if two files in the git repo point to the same git-annex
object, it has to make a copy of the object to one of the worktree files.
"""]]