Documentation of Rules API Changes from 6.x-1.x-dev to 7.x-2.x-dev

Hey fago and everyone,

We've been looking to port the Private Message module (http://drupal.org/project/privatemsg) to work with Rules 7.x-2.x-dev (Private Message already has Rules integration in the 6.x version), but it's been difficult to find documentation on the API changes from 6.x-1.x-dev to 7.x-2.x-dev. Does anyone know where to look?

I've found rules.api.php in the Rules 7.x-2.x-dev module itself, but I was wondering if there was maybe some additional documentation somewhere else.

Thanks,
Ben

P.S. Fago, it was great to meet you and chat at DrupalCon San Francisco!