The default error (e.g. 404) pages in OpenBSD's built-in web server are super basic. I can live with that, but what I can't live with is that they use Comic Sans. I kid you not.

I don't know if it's supposed to be a joke, but it's not funny.

If you do a search for "httpd custom 404 page" you'll find a lot of responses claiming that changing error pages can't be done without patching httpd and recompiling. Well I'm not doing that!

On about page 4 of search results I found this post explaining how to do it. Turns out it's now possible with a simple config change:

Just add something like errdocs "/errdocs" in httpd.conf. Then put a file named err.html file in /var/www/errdocs with the generic error message or create one for each error code, e.g. 404.html.

I could have just read the man page httpd.conf(5) and saved myself a lot of trouble.