We been doing a #jslang session at #jscc25 and built the Intl.PluralRules #kata
The code we wrote is here:
https://codeberg.org/wolframkriesing/jslang-meetups/src/branch/main/Intl-PluralRules-jscc25/test.js
It took us a while to grasp the meaning of the API, it feels quite high-level and still needs a lot of manual work. I am personally not so convinced that the PluralRules is that much of a leap forward.