Is there any way through Extendscript (supported or unsupported) to access caption track/layers? Specifically for my script I'd want to delete all captions or turn off the caption layer entirely. Or if there's any other automated way to do this in an extension I'm working on?
There is no ExtendScript API around Captions; no date has yet been established, for the availability of any UXP-based Captions API.
Is there any way through Extendscript to change caption track/layer name from default "Subtitle"?
No, the previous answer still stands.