They got the URL wrong.

https://repl.it/python 404s and I rather suspect they support python. ;)

https://repl.it/languages/perl6 and https://repl.it/languages/raku both work. :)

They're both 2019.03.1 so their "raku" is presumably raku in name only. (Eg doesn't support $*RAKU etc.) Be nice to see it upgraded to a real 2020 raku.