The #Micropub "server" was based on @adactio's minimal micropub endpoint gist: https://gist.github.com/adactio/8168e6b78da7b16a4644
(mostly because I wanted to understand the mechanics of Micropub)

For auth + token, I didn't want to depend on 3rd party silos, so tried #SelfAuth and #MiniToken. Basic tests worked, but failed horribly with real-world #Micropub client, e.g. #Quill.
https://github.com/Inklings-io/selfauth
https://github.com/Zegnat/php-mintoken

So ended up using the de facto https://indieauth.com/ for auth + token. C'est la vie. 🤷‍♂️