For those unaware, Undeadly.org is a very unusually engineered site. It's written in C, and it runs under FastCGI on OpenBSD's (edit: home-grown) httpd.
FWIW, OpenBSD hasn't used [a fork of] Apache in nearly 10 years. Since OpenBSD 5.6 /usr/sbin/httpd has been a homegrown HTTP server, originally based in part on relayd, an HTTP proxy and another bespoke OpenBSD project. OpenBSD httpd can only serve static files or forward requests to a FastCGI handler.