Nevermind.

https://blog.nodebb.org/introducing-the-build-system-in-v1-4-3/

Scaling - NodeBB Documentation

Documentation portal for NodeBB Forum Software

(docs.nodebb.org)

There seems to have been a change in 1.5 that prevents access to things inside nodebb/public if the file is not known by NodeBB. I'm using Let's Encrypt for HTTPS certs and I have the .well-known folder symlinked into public/.well-known so that Certbot is able to make the verification by accessing a file from it e.g. http://domain.tld/.well-known/some-long-hashed-file-name.

How can I make NodeBB serve from that path without returning 404s?

I can work around it with Nginx proxy hackery, but I'd like this solved on NodeBB's side.