Opera, before it got Chrome-ified, had a built in web server. I used it to share files with my buddies. Super simple. Didn't support scripts IIRC but with weba

Opera, before it got Chrome-ified, had a built in web server. I used it to share files with my buddies. Super simple. Didn't support scripts IIRC but with webassembly it doesn't have to be too difficult to support something like NextCloud I'd think.