Maybe I'm being obtuse, but I can't figure out what the app does. Can you give me a For Dummies TL;DR?

Ah, okay. @ChipTuner @Finrod Felagund @MichaelJ are who you're looking for, on this.

Oh yeah, there are a handful of these types of apps. There are even pseudo commercial services that use cf workers to get a reverse proxy to run a server in your browser. Stuff's whack.

I was playing with this one yesterday. It was cool to run a python script on one machine in 2 seconds, have it gen a QR code I scanned with my iPhone and bring up safari with a UI that directly reflected what files were in my repository. And THEN pop in that same IP addy on an old Windows machine and see the exact same interface in an out of date browser.

Yeah I've used a tool called miniserve. It's a single file executable that does something similar!

I wish I could use that IP address to point my Obsidian vault to. Sadly, Obsidian doesn't have that capability but it'd be cool if it did.