Update, I found a link to the camrip of it. No subs though so it's on you to understand the Japanese, but I uploaded it to Tankietube: https://tankie.tube/w/t3dKNtc5APRzWnfqL5nMku

spoiler

From what I gather, it is after EoE and Asuka's still struggling with her feelings for Shinji vis-à-vis a discussion between herself and Asuka the Eva Pilot (Don't quote me I can barely understand every 5th word). There's a cute goated moment at the end for all the Shinji-Asuka shippers (me) where she's waiting for him at the train station and when he shows up & offers her his hand, she envisions their future together As an EoE fan I rate it 10/10 because I don't really vibe with Mari even though canonically I guess she's supposed to be Shinji's true love (or at least Anno's lol)

The Asuka short was shown at the anniversary event and supposedly they were real strict about no one recording it & threatened to sue anyone who posted it online. I haven't been able to find anything on it either besides the fact that it is supposedly titled Episode 27 (as it is written as a bookend to Asuka of the original/EoE continuity)

Supposedly it will get some sort of physical release though according to Japanese twitter users who managed to see it at the event so

I could only find these terrible screencaps, not sure if these are from the event (but it looks like it given the instruments on stage in front of the screen)

source: https://x.com/GusElMismisimo/status/2025684206341300598/photo/2