I really liked Hugo docs’ representations of file trees, so I recreated it in CSS using nested lists to make the markup more accessible: https://codepen.io/heydon/pen/PjLVWm/
The thing I’m working on uses a simple shortcode to let you make file tree representations using lists in markdown:
{{% fileTree %}}
* Top level
* Second level
* Second level
* Third level
* Top level
{{% /fileTree %}}
Note that the only limitation is the number of vertical lines drawn in the pseudo-content for the <ul>s. You can add more if you think your use case will need it. Currently it allows 20 files or folders in one vertical set.