Bloom's "new Content Licensing system"

I’ve just noticed the following in the 4.7 release notes:

In all publish screens, if a book uses Bloom’s new Content Licensing system, Bloom will prevent publishing a language that has not yet been licensed for that book. This will prevent accidental violation of license agreements in which a publisher needs to limit which languages are published. For example, they may allow minority language translations to be Creative Commons licensed while relying on sales of the original English version for company revenue.

Can you provide more information about this system and how to use it, please?