alt Hacker NewsThe page provides useful information. It tells you where you can download the XScreenSaver source code (from https://www.jwz.org/xscreensaver/), and how you can send patches (via email)
It doesn't need to provide anything else. Nobody is required to sign up to your preferred platform, or make their work available in a way you prefer to consume it. Get over yourself. If you want to contribute, contribute as requested. Or don't, the license allows you to host your own version, just be clear it's your version.
JWZ went to great lengths on github.com, solely because some other shitheel registered the "xscreensaver" organisation and went out of their way to make it seem like it's official, and github.com's google juice means it outranks the real site. Hence the need for the effort to solve that problem (reputation management and SEO after a copycat misrepresents themselves as you)
Putting a repo on Github, versus putting a notice on Github that there's no repo, does not change the risk of people installing malware. While someone else still has the top ranked page for your software, they remain the most likely place a moron in a hurry[0] will download from. You adding a repo doesn't help, you getting their repo removed, and salting it to prevent recreation, does help.