Years ago (20 or so, by my recollection), there was a list of "95 chemicals that major brewers use but don't have to divulge" that was easily accessible on the intrawebz. I can't seem to find it now, but there are additives in Budweiser that are not listed on the label, including heading agents (how else would something so devoid of body actually form a head?).
The same is true of fining agents and other such things added. Probably not very much in the finished product, but it's in there...
The same is true of fining agents and other such things added. Probably not very much in the finished product, but it's in there...