Thanks for that roundup, @Girx! There's a lot that has happened in the SVG world since I dared to call myself an expert on the subject.

Well, I found something in the MediaWiki API that looks closer (from this API call). What I see:

Per my comments in T308081, I agree with @Quiddity that after looking a user up on Special:CentralAuth, the dates for users (e.g. Special:CentralAuth/RobLa) should point to the registration date or perhaps the "first edit" date. As it stands, the date (when hooked up to SUL for a specific user database) is misleading for everyone who edited Wikipedia prior to the 2015 SUL finalization, and it takes a Wikimedia Foundation history nerd (or someone who was there at the time) to understand how to use the date that's shown. Given how long it's been since the 2015 SUL finalization, there really not a great reasons for showing the "SUL attachment" date so prevalently without showing the "first edit" date (which is much more important, and more likely to be the thing that the user is interested in).

I've been thinking about picking up development of this extension again, and I'd appreciate it if it weren't deleted. Many of my personal copies of the source code were stored in "the cloud" (e.g. at a website that Atlassian purchase), and while I could piece together the old history, I would appreciate having the source code here. Plus, y'all seemed to have updated my old source code to handle versions of PHP newer than PHP4 (which I appreciate).