Well, I certainly don't want to break existing packs, but in the end I left the index api (double checking).  You are correct it isn't needed, because the pack added is a core pack.  The loading order may effect your pack loading.

Maybe I should understand how existing packs do it.  I'm guessing any added patterns are added last?  Do you even have the case of more than one pattern file loading at the end.

Need tests any way we slice this.