It is the jclouds [JustProvider](https://github.com/jclouds/jclouds/blob/master/core/src/main/java/org/jclouds/location/suppliers/all/JustProvider.java) :) The typical location hierarchy is Provider > Region > Location.
This `JustProvider` supplier returns the "provider" location (DigitalOcean in this case) that can be set as the parent of all regions, to make them properly scoped to the provider.