Allowing an extension changes the error response from 403 to 404 for me.
Only extensions from in the original list get a 404 response.
I edited `/opt/webinoly/webinoly.conf` and ran
sudo webinoly -server-reset
I see nothing in any of the nginx logs, neither in the error, nor access log.
Changing the extension allows file to be downloaded, meaning it does not appear to be a permission issue.
Something else I discovered:
Leaving the extension list blank is the same as leaving it default. Either I don't know how to input a blank value or you need to put some nonsense placeholder there.
Edit: I went for ngingx debug level. But I cannot answer my own question. I made my own custom config. With a root directive. But my root directive gets overriden by common/headers.conf; for some file extensions, sending my requests from my defined root back to htdocs.
I was able to download some of my files and not others, which is just awfully arbitrary.