I’d guess it’d be a particular collation, rather than Unicode order…otherwise ö would always come after z (which is incorrect for English, but correct for, e.g., Swedish).
That or being logged in. It was “not found” for me, too, until I logged in. (I don’t have any rep on the Ubuntu site, aside from the 100 for being on other SE sites).
nil Objective-C objects, too. Also, logging a signed int in Xcode 15 (for me) ends up being displayed as unsigned if os_log_* or NSLog are used (appears fine in Console.app, though, thankfully).
Wired story about the origin of the cards: https://www.wired.com/2007/06/lock-pick-busin/ (I looked it up because I thought they looked like some cards someone I knew designed, and sure enough…)