At least one use of Indexable (by whatever name, but this rolls off the tongue the easiest) would be the metaclass in typing.py that allows one to write List[int] -- there's no containter here!

The "drowning out" seems purely subjective -- perhaps if you order the contents of the module alphabetically you won't get much insight, but the docs should use a better organizing principle than that. (After all alphabetization was invented as a crutch for searching. :-)