Alien: according to their marketing literature, it is a phenidone-ascorbic acid type developer. If you are looking for something to home-brew, you can try Mytol (it's in the recipes section of this site) -- it's an Xtol clone. You can separate the phenidone and sodium ascorbate components into one concentrate and the rest of the ingredients into another. Or you can try something like PC-TEA or PC-Glycol.