This is a static webpage you can access at https://karamoshi-nakatoto.github.io/subway-biscuit/
You can also self-host it by cloning the repo and using an http server of your choice (nginx, Apache etc.) or you can use the provided Docker image:
$ docker run -d -p 80:80 ghcr.io/karamoshi-nakatoto/subway-biscuit:latest