How to see what web server is running on my mac?

I'm trying to learn how to create a custom WordPress theme. I've been following a tutorial, and I was trying to install DesktopServer onto my MacBook Pro (to create a local environment.) But I'm not able to install it because it's stating that "It appears that you have another web server already running. DesktopServer cannot be installed. Check that you do not have Web Sharing turned on from your System Preference -> Sharing control panel or turn off and remove your other web server."

I've checked my Sharing settings, and nothing is enabled (including internet sharing.) So that must mean I have a web server already running. But I don't know what that would be.

Is there a way for me to find out what web server my mac is running? And after that, is there a way for me to disable that so I could possibly use DesktopServer instead.

I've really good with writing HTML, CSS, Javascript, etc., but I'm pretty new to the server and hosting and stuff. I honestly don't understand everything yet. Any help will be appreciated. Thanks!