The thing is that pretty much all Fortran is "some obscure edge case". Otherwise it'd be written in something that's not Fortran.

Another example, I know the guy who maintains NIST's fluid properties solver (back in the day he worked at a subcontractor for NASA characterizing superfluids in fuel tanks). It's ancient Fortran compiled to a windows .dll and wrapped in VB in an excel file. It's super battle tested (being used for nearly 30 years), and it'd be awesome to be exposed in the browser.