Your inventory (so called MARKET file) its where game takes info about which chars are unlocked for your account
Full profile storing info mainly about game items/addons/offerings/char Prestige levels/and few special cosmetics like L3 and P3.
Currently theres no public permanent method to add something to your Market file.
You can only "hotswap" ur original Market file with your local tampered version of it...
But as i said this method is temporary and needs to be done each time u start the game.