I dare say this is a newbie question but I've not found anyone else asking it.
I am going through a steep learning curve having just taken over a site running magento 2.2.6 on magestack on nginx (none of which I know!).
There is an extension which is creating a google shopping feed in
/pub/feeds/ but although I can download it over ftp, the feed file returns a 404 to a browser so I infer that google won't be able to pull it.
I already hit the same issue trying to verify the site with the google merchant account by uploading a file to the root (which also returned a 404) but I was able to work around that with a tag instead.
nginx doesn't have htaccess files and if it were something every magento operator had to do I think my searching would have turned something up by now, so any pointers to what's going on would be appreciated.
Edit: having set up a fresh install I see that it's not default magento behaviour.
nginx configuration can include location rules to route urls to paths. In this case the magento root is the domain root and the configuration routes requests to eg.
domain.com/media/catalog/product/1/1/image.jpg to the path
It's set up so that any routes without a matching rule return a 404
so that a further location rule would be needed to route requests to pub