That is rather annoying and confusing, but to be fair to @jlgarnier, that acronym was first used by either @tophee or @pfaffman in Using Nginx Proxy Manager to manage multiple sites with Discourse to refer to Nginx Proxy Manager. I don’t love it, but if it is ‘wrong’, that isn’t really OP’s fault.
For example, the topic has a section called Install NPM focusing entirely on Nginx Proxy Manager.