The modifications on this site are all very tightly wound together. It isn't a matter of just clicking a button and having a modification all neatly ready to be offered to the masses. The author(s) of some of the modifications on this site have decided to not try to figure out how to split all the mods apart and make them work independently of each other so that they can be offered for download. At least, that is what I understand about them. Some of them have been offered up for download - just check out Princeton's lists of modifications, but some of the more complicated mods are just too hard to separate out from all the others or do what is necessary to make them generic enough to work for others.