I'm not finding it with a bit of searching. If you saw it on Khan Academy, it's likely an unreleased game that LSAC provided to them. Otherwise, it might be written by a prep company and unofficial.
Look at the Khan Academy page on it, it's really brief. The gist of it is to have 1 paragraph arguing your side, 1 paragraph arguing against the other side.
Thanks for the response! So I did a diagnostic on Kahn Academy a few days ago and scored a 156. I would like to do it again to get more personalized recommendations here, are you referring to the test from 2007 in the curriculum?