Site dependencies (clone/download directly to web directory)
Parsedown (git clone https://github.com/erusev/parsedown)
Mdjs (git clone https://github.com/hangxingliu/mdjs)
x3dom (wget https://x3dom.org/download/1.8.1/x3dom.{debug.js,css})

Web dependencies:
PHP
PHP curl module
PHP MariaDB/MySQL module

System dependencies (just need to be installed and findable in path)
assimp (to convert 3D models to a common format for preview generation)
One of: povray, openscad (to generate previews)