Due to the QML possible exploits, a version released removed the ability for non-marketplace QML files to be loaded.

However, this makes testing online QML files impossible, since the files would have to be in part of a "released" product on the marketplace, and thus cannot be tested even by marketplace validators!

For both the people testing marketplace items and for people who are working on marketplace QML based items, a lack of a way to add additional URLs to the whitelist is a problem that should be fixed.