Should it have a folder view when it doesn't have an index.html?

Jsut like most web servers, I want a default file/folder list at the mounted path.

The issue names no files, tests, or entry points. Start by locating the static middleware and its existing directory and index-file handling, then review related tests. Done means a mounted path without index.html presents a default file or folder listing, with coverage for that behavior.

Written by the indexing model from the issue text.