First two questions in Jonathan Blow Q&A on "Making Programming Language Parsers, etc" <https://www.youtube.com/watch?v=lcF-HzlFYKE>.
Jonathan's freeform answer to the first question is correct. The only correct answer to the second question is, funnily enough, "something that runs in the web browser" (and the reason why it is correct lies in the question/answer pair of the first question).
XXX @58:00 <https://youtu.be/lcF-HzlFYKE?t=3480>"