How is a Kotlin multi-platform library distributed/deployed ❔

Maven, actually. I've been working on it myself and I have deployment up and running - check out what I did here: https://github.com/UnknownJoe796/kotlinx.

What is the bintray URL for your libraries?

It's not posted to bintray yet. It's still in really really early development

You can look at this multiplatfrom project: https://github.com/kotlin/kotlinx.serialization