Aja output not functioning in new plugin

Does anybody know what is the upper left corner overlay with this strange “square counters”? It seems like some valuable content (maybe UE embeds something there for help AJA to sync video?). What it does?

It seems some kind of signaling but is nothing that I’ve ever previously seen (WSS, AFD, etc). It will be always there? Any plans of moving this into a less visible place?

258556-aja-square-signaling.gif