I have code that could benefit from knowing how many days a given month has. This is not as trivial as it may sound; every 4 years, February has 29 days instead of 28 for example. And throughout history, there have been unusual years with slightly different days per month. (This is one example for why you should never write your own datetime / calendar code, and instead use existing libraries.)
kotlinx.datetime has great functionality for local datetime timestamps, timezones etc. but I did not find anything for this problem. I’d like to use something multiplatform-compatible if possible.