I have now found time to read into the paper, however, as this is not my usual business I am not claiming to fully understood it. What I did understood is that they are adding an additional long-range gravitational potential to the scene which will alter things far away of something supposed to be mainly dark matter. Dark matter itself so is the theory follows general relativity to the letter so the distribution of dark matter around a galaxy or another heavy object is determined by it giving cause to a potential to be expected at longer distance. This is where the suggestion of the authors alters things and as such, this would be measureable.