In what format are subtitle files saved for feature film dvds?

This is a multi-part question. Many thanks if you could read to the end before answering...

A Chinese film is made, then it goes into the editing suite where Chinese and English subtitles are burned onto the film with correct timing, font, etc.

The software used could be Final Cut, Premiere, Sony Vegas, whatever...

Would there be an exportable subtitle file that could be edited by someone elsewhere, sent back to the editing suite to be put back onto the video?

If so, what format/file extension would the subtitles be?

If so, would the format depend on the software used? In other words, if the editing suite uses Final Cut, but someone wanted to edit the subtitle file on a Windows machine (i.e. not using Final Cut because it's Mac-only software) would that be possible?

Thanks in advance for your answers.