title: difference between `-- and +-- after running npm list
body: <p>Whilst addressing GitHub dependabot updates, I've been looking through the dependencies list created after running <code>npm ls -a</code>.</p>
  <p>I (think I) understand the nesting involved: a pipe indicates that packages below are part of the dependencies list, and so on.</p>
  <p><a href="https://i.stack.imgur.com/7ytee.png" rel="nofollow noreferrer">see image created from running <code>npm ls -a &gt; file.txt</code></a></p>
  <p>What I don't understand is the difference between +-- and `--.</p>
  <p>After looking at it for the best part of an hour (embarassingly) my best guess is that `-- indicates the last package in a given nesting, whilst +-- is an indication there are more packages.</p>
  <p>It would be great if anybody could help clarify and enlighten me on what's getting output here.</p>