I completely forgot about this anniversary until someone pointed it out to me, which is why this post is two days late!
Now here's a really sad story: I don't have a copy of XScreenSaver 1.0! The oldest version I have is 1.17 from 1993.
That first version was served from the FTP server export.lcs.mit.edu but I can't find an archive of that anywhere. It may also have been uploaded to comp.sources.x, but again, archives from 1992 seem to not exist at all. Probably there's an ISO of some Linux distro from 1992 or 1993 that still has the source of these versions, but if there is, I have not found it.
Go search, please!
I wasn't even able to find the unadulterated version of that original announcement post, only the mangled version on Google's debasement of the USENET archives.
If you can find an archive of comp.windows.x.announce or comp.sources.x from 1992, particularly one that shows the original Message-IDs, please let me know. I checked Internet Archive but found nothing good.
And here's what appears to be my first XScreenSaver-related LiveJournal post but that's from only twenty years ago. 4.03.
So my first thought was to fire up the oldest computer I still own and shoot a video of XScreenSaver running on that. I pulled my SGI Indy and SGI O2 off the shelf, but though they both make the still-delightful startup chime, I don't have a VGA monitor (or a PS/2 mouse...) and neither of them wants to play nice with the VGA to HDMI adapter I have. The Indy displays solid black, the O2 solid green. Beats me!
(A reminder that XScreenSaver predates not only HDMI, but USB...)
So instead, here are a couple of YouTube videos of what might be my first two screen savers. Imagine these running in 1-bit monochrome on a 960x640 CRT.
I probably wrote the first line of code in April or May 1991. If a time traveller had told me then, "this will be your life's work", I probably would have been as surprised by that as by ...gestures wildly... the Current State Of Affairs.