While he doesn't really contribute code to Ruby itself anymore, the language founder is a proponent of programming with LLMs. He does so in the language spin-off mruby quite heavily.
Ruby itself contains commits co-authored by Claude, contributed by a core maintainer.
TruffleRuby, an alternative language implementation, contains code by Copilot, contributed by the project lead.
JRuby is not listed as an alternative because, while its lead is a vocal critic of LLMs for code generation, he appears open to it still and has also posted about using them for things (that might not be JRuby, tbf).
