<code>vendor</code>, which is the default when a workspace <code>vendor</code>
  directory is present.
</p>
<p>
  Note that the <code>vendor</code> directory's contents for a workspace are different
  from those of a single module: if the directory at the root of a workspace also
  contains one of the modules in the workspace, its <code>vendor</code> directory
  can contain the dependencies of either the workspace or of the module,
  but not both.
</p>