We both have to not use "both", as well as "as well as", and also, never with an added extra comma, too, either.
And "dragons lie" (not "lies"), though a forked tongue have some.
Yet, the words, themselves, are getting in the way of this already way ambiguous description that should explain in more detail that:

    /** The set of plan bytes is explicitly maintained in MRU-first order, while also indexed by the plans' bytes. **/