The index of implementation defined behavior is crowded with things that do not elicit behavior, such as the values or types associated with specific names. Suggest pulling out all the implementation defined entities into their own index, or perhaps two indices, one for types and another for values, to save prefixing each entry as "type of" or "value of".

Note that this is a more pronounced issue for types than values, so a single index of implementation defined entities may seem the neatest use of space.