The beta profiles are intended to reduce banding and highlight color artifacts that appear in some images processed using Adobe Camera Raw and Lightroom. They're a work in progress, with feedback being actively solicited in the Adobe forums. Users should note that as compared to earlier profiles, the new betas may appear to produce images with slightly brighter highlights.

If you're interested in testing the beta profiles out, you can find the downloads along with details on how to install them in the Adobe forums.