Add support for non-cape cosmetics
While OptiFine only has capes for the general public, some users have other models attached to their player (OF calls them "items"). I think sp614x has to add the items manually, but they are available on Optifine's Servers at http://s.optifine.net/users/USERNAME.cfg. I understand this is not the point of the mod, but I think it would be a fun enhancement.
I'm aware since Christmas last year but OF doesn't use JSON models like vanilla does, so an adapter would be a lot of work, and I'd have to reverse the model format and... it would be a big pain, yes.
Also I've been thinking of adding them recently either way so hooray!
AFAIK they use the JEM format (you probably already know that), but it is a model format made specifically by OptiFine for OptiFine