Lost and found
I was reminded the other day that I needed to get a 404 page done. So far, I have just been letting Github Pages do its job and present a Page not found page whenever a visitor types in a faulty URL, hits a broken link, or in any other way ends up on a page that doesn't exist on this site.
There is a guide on Github Pages on how to set up a 404 page, and all in all it was done within a few minutes. Next step will be to add something creative to the page, but for now at least I have something else than the default page.