Four engine projects turn out to have a website, or a browser build, or both
Julius, Augustus, Akhenaten and the Caesar II port each carry something beyond the bare GitHub repo - a project site, a WebAssembly build you can run with no install, or both. Checked by hand rather than guessed from a github.io URL pattern; the other seven engine projects genuinely have neither.
Every engine card has always shown one link - Repository - which undersold a few of these projects. Augustus's own homepage isn't a landing page at all: augustus.josecadete.net is the player itself, a drag-and-drop box for a C3 folder that runs the game in the browser on load. The Caesar II port's github.io page is the same shape. Akhenaten's site is a proper one - About, Devblog, Wiki, Screenshots, Downloads - with its own separate /play/ route for the browser build, so it needed both a Website and a Play in browser link where Augustus only needed one. Julius's own domain turned out to be a development-builds page (zip downloads per platform, including an Emscripten build with no embedded player) rather than a marketing site or a playable one, so it's labelled Website and nothing more.
Checking meant reading each README for outbound links rather than trying `<username>.github.io/<repo>` and seeing what resolved - Olympus, eZeus, CityBuilderEngine, both Ozymandias forks and OpenPharaoh have no non-GitHub link in their README at all, and a guessed URL for any of them would have either 404'd or, worse, silently resolved to something unrelated on someone's personal github.io. Two new optional fields, `websiteUrl` and `playUrl`, carry `null` rather than being left off for the seven that have neither - the same explicit-absence pattern `docsUrl` already set.