Shows open and closing price; controls for extensions. Toggles for visibility.
Shades opening day gap, controls for extensions. Toggles for visibility.
Does not work for hourly or above as opening price is set to 9:30 am eastern which does not appear on the axis for hourly or above. And I'm not a coder.
But for sub hourly charts - it's an easy tool I've been looking for for a while just for myself.
It's imperfect; but sharing for anyone that was looking for something similar.