We plan to add more RESTBase endpoints to support the new "Explore feeds" feature in the apps. The currently proposed names are listed in [1]. It introduces a new top-level hierarchy, called "project".
If you have issues with the current proposal or ideas to improve them please comment on the Phab ticket by Thursday, May 19, 2016.
[1] https://phabricator.wikimedia.org/T132597
Thank you, Bernd Sitzmann Android app & Mobile Content Service