Changing / adding biomes to Al's Enderman Revamped?

Hi, I apologize if this is not the right place to ask this, but I am trying to use AL's enderman revamped, a texture pack that adds biome dependant enderman variants, with several new biomes, and trying to add some of them to the list of biomes. It uses optifine to do this.
However, I don't really understand the syntax of the biomes list, as they are just the name of the biome with no underscores or anything? Like SmallEndIslands. So how can I add biomes not in vanilla to a list like this?