Goal-based adaptivity in Fluidity

[gnikit]

I was wondering if someone could shed some light into what the goal_based_adaptivity option which is in the schema under /mesh_adaptivity/hr_adaptivity is doing.
Is the implementation supposed to be a Dual Weighted Residual (peeking into Goal_metric.F90 seems to indicate that this is some residual based a posteriori estimator), has anything been published by the AMCG on Fluidity's goal-based adaptivity?

Any help/input will be greatly appreciated, since I couldn't find any info on my own.