initializer list - Why are these C++ headers specified to include <initializer_list>? -

as can seen https://stackoverflow.com/a/26614984/481267 following headers guaranteed standard #include <initializer_list>:

• everything in [containers]
• <utility>
• <string>
• <algorithm>
• <random>
• <valarray>
• <regex>

most of these headers declare @ least 1 function takes std::initializer_list<e> argument, makes sense. however,

• <array>, <stack>, , <queue> have no such functions, although perhaps makes sense treat containers uniformly here.
• <utility> has no such functions.
• <iterator> have functions initializer_list argument (rbegin, rend) it's not specified include <initializer_list>.

what rationale behind these exceptions?

seems there no explicit rationale, proposals additions standard made , proposals accepted.

at end of document n2672 initializer list proposed wording says:

in 20.2 utility components [utility] paragraph 1:

this subclause contains basic function , class templates used throughout rest of library.

header <utility> synopsis

     #include<initializer_list>       namespace std { 

so, authors of paper saw initializer_list utility, , ought included <utility> header. , therefore is.

the paper didn't propose changes <iterator> header, none made.