Yann Büchau 
#InfCloud hasn't been updated for a decade, yikes. But apparently it's still the *only* available statically servable (i.e. no database / no PHP / whatever) #CalDAV #CardDAV web client out there. 😱
The code is also... interesting. There's so much hard-coding going on, but maybe that's how you do web dev 😅 I made a #nix package you can override with some useful options such as increasing the animation speed and allowing vCard 4.0 support.
