Between Blender 2.78a and 2.78b, the RNA datablocks have disappeared from the Outliner (or been moved somewhere I don't know), and they didn't come back since then. What's the reason for that ? There's no precision about it in the release notes.
I believe they were removed from the outliner display to improve the drawing speed.
I have been using the Development tools API navigator to get access to the RNA information.