Add a wiki that doesn't use the Gregorian calendar to beta cluster. Thwiki would qualify, where it's currently 11 มกราคม 2565. No content needed. Many things can (or do) assume the Gregorian calendar so this is needed to test whether they fail when the calendar is something else.
Do you plan to use that wiki for some specific tests? Is there anyone else planning to? Setting up a wiki is non-trivial work, and we shouldn't do that just because theoretically someone might need it.
I'd use it to test Bawl (which locates comments in wikitext based on the UTC timestamps as provided by DiscussionTools), but if the admins of thwiki/thwikibooks/etc don't mind a few dozen (maybe more, hard to say) test edits in userspace that would work too. Can you give me immunity in case they do mind? I'll see if I can find an admin on a Thai project who understands English so I can ask for permission.
Edit: nevermind I guess. The Thai solar calendar uses the same months and days as the Gregorian calendar. So I already fixed it. I just skipped the year. 🤣 There could still be other calendars to get me into trouble though, but Thai solar is no longer among them.
I'm not sure why @Base added themselves as a subscriber, but I can sense that unless someone else has a compelling argument this request can be closed. For Bawl specifically, it supports dry runs anyway. Not always conclusive and a little less convenient to analyze, but with dry runs I suppose I can limit the number of actual edits sufficiently to avoid pissing off admins on any production project. Unless I screw something up and start editing in an infinite loop. But for that there's YOLO.