Thankfully it's been a couple years since I had to touch a WordPress code base, but I remember being confused because I needed to define a route and couldn't figure out how to do so either in the code base or in documentation scattered about online. Eventually I realized that this was because WORDPRESS DOESN'T HAVE A ROUTER and you're supposed to just create .php files which are called and executed directly from the web server. True caveman smash-together-rocks shit.
This is not true. WordPress routes request in its own, admittedly shitty way, but it has a router. I don't remember where it is, but it exists. It parses rewrite rules and matches them against the request URI.
