PM sent. The main subtitles are in PGS format, but there are also SRT files for those who need a text format. I didn’t find any of the text subtitle formats were really adequate for this project*, so I’m not going to provide anything beyond SRT, not that you couldn’t make them if you wanted them badly enough. PGS can be used directly with software players like MPC-HC, you just add it as an external subtitle, just as you would an external text file–it’s not just for Blu-rays.
* My main complaint about text formats is that I like to keep content and formatting as separate as possible, as it makes managing huge projects like this a lot easier (think CSS). That’s why I actually prefer a “dumb” format like SRT, and manage layout through various external scripts. But there’s some other more corner cases where I just don’t like text formats too.