"PaLM 2’s improved multilingual capabilities are allowing us to expand Bard to new languages, starting today. Plus, it’s powering our recently announced coding update."
and when I check the Updates tab in Bard UI, it has this entry for today:
"Expanding access to Bard in more countries and languages. You can now collaborate with Bard in Japanese and Korean, in addition to US English. We have also expanded access to Bard in all three languages to over 180 countries."
which seems to strongly imply that it is, indeed, PaLM 2. Just to be sure, I gave it the same puzzle in Korean, and got a similarly lackluster response.