is there a media type for XSL-FO?

[Arnd Beißner]

A few years ago I was looking for the same thing and like you ended up
empty. While XSL-FO as a formatting language is certainly an intermediary
language that is rarely actually stored or requested, there are a few
cases where one still wants a media type for it. The scenario I wanted it
for was for storing reference documents for automated testing.