What?
CiviCRM core now offers a Continuous Integration service to partner & member organisations on their extensions. The service will run the unit tests associated with an extension whenever a PR is submitted to that extension. This is similar to the process that runs on core and is driven by jenkins and runs on the same test infrastructure. There are free services that do this (e.g Travis) on github in general but they don’t provide the CiviCRM setup and database environment that is needed to run tests on CiviCRM.
Why?