We are talking about this product from Fab-Defense:
https://www.fab-defense.com/en/category-foregrips/id-2094/improved-mag-well-grip.html
It is at it core it is an extended magazine-well for a standard AR-15 lower. It extends and widens the opening of the magazine well to help guide a magazine into the mag well. It is most advantageous for shooters trying to rapidly reload their AR as is typical encountered in timed shooting competitions. An additional feature of this particular extended magazine-well is that is has a cosmetic overlay that can be easily changed out to change the external appearance of the magazine well. My 'friend" has four options for this cosmetic overlay as pictured in the first post to the thread and I was wondering which the forum would use in my "friend's" place.
And I have to say the result so far are somewhat perplexing with the plain-jane winning. I am not sure you guys appreciate just how savage and merciless those USPSA metric targets can be and any small additional intimidation factor might be the difference between victory and some savage paper cuts.