And why is Python mentioned twice? Okay, Python 2 is not the same as Python 3. I get it, but still... And again, ECMAScript and JavaScript are basically the same thing. lol
OP here.
I found two lists of supported languages on their site:
The dropdown in their code editor which is reproduced in full including both python versions,
and a list of environments which includes things like bash and "vanilla js" or ECMAScript which I added to the first list.