what is the correct css scope for footnotes in rstudio's rmarkdown?

I'm making my own rstheme, and I'm unable to find the correct css scope to change footnote markup in RStudio's rmarkdown. I'm aware RStudio follows ace-editor css scopes, but the documentation I've found doesn't seem to include markdown footnotes. Textmate and Sublime Text have scopes that capture footnotes, but their scopes do not transfer over to RStudio's. None of the rsthemes I've looked at as models seem to touch this either. I've tried many different combinations, but with no luck. The notation style I'm using is simply:

There is a footnote named "fn1" at the end of this sentence that begins with a caret and is enclosed in square brackets.[^fn1]

[^fn1]: This is the footnote.

Is there a scope for footnotes, or is it not implemented? Or, is it a problem with the "flavor" of footnote I'm using? If it's not implemented, I'd like to suggest adding a note to this effect on RStudio's custom theming page.