JSON and XML already provide great expressiveness for external information. Unfortunately, both are rather nasty configuration languages as they are full of syntactic sugar (all the angle brackets and quotes in XML, all the quotes on keys for JSON) and JSON not even supports comments. The de-facto standard for configuration files today is neither XML nor JSON. It is YAML since many years, as it provides the same expressiveness as JSON/XML (fully nested structures) but with a syntax which uses a minimum of syntactic sugar. Hence, please support YAML as an additional format of external information in the Data Sources. This would be much more user-friendly.