make the copypasta for performing releases more literal about directories.  remove use of = sign, it makes tabcomplete harder for most people.  use a directory instead of a file in the first example, because that's often the first question.
make a note about using a swap space -outside- of the release repo.
manually linewrap the longform explanation of hash mismatch warning emitted by the mdm update command.
define a failing test for switching to branches that leaves a dependency unlinked, looking towards addressing this as a feature in the near future.

currently, mdm leaves the working tree alone.  it's a situation where the config defining the desired state is versioned, and there's a tool dragging the world along behind it: absense of config is different than config for removal.  Other dependency managers have similar issues; concretely, I tried ivy once and was surprised to discover my working tree stayed rather un-gc'd (though of course usually that goes somewhere under your homedir; it's better if you don't make eye contact, right?); and I've seen blogs describing the issue for devops tools as well; basically I don't feel alone in this issue.

but, i think we might be able to do something clever with dropping an owned-by-mdm flag in the git data dir of dependency submodules.  that would give us enough information to know what we can safely remove (vs what's a submodule we don't own, or what's another git repo just hanging out).  solution still needed for how to actually detect the submodule repos once on a branch that's missing the gitlink, though -- the current SubmoduleWalk code path won't cut it for that.
create a new test fixture repo that contains a series of commits.
sanity test against how submodule merging usually works in plain git.
Merge branch 'doc'