Haven't seen this discussed, did we miss something?

Jim's video of 14 Dec 2019. Top line is obviously "2019,12,14." Xes are thousands, deltas are tens… ones are, well, ones. And that backwards seven thing must be a five–have pored over Unicode trying to figure out what it is with no luck. Obviously a number system, but not one I'm familiar with.

Is this significant, or is it just Jim being Jim?