Copying the content of my std-discussion message:

The aforementioned paragraph contains this example

struct X { };
struct B { operator X(); };
B b;
X x({b});         // error: B::operator X() is not a candidate

I think that is supposed to demonstrate the last bullet, "the second
phase of [over.match.list] when the initializer list has exactly one
element ...". However there are at least two problems with the example

1. The move and copy constructor is not a candidate by
   [over.match.list] but by [over.match.ctor]
2. X is an aggregate, so the reason that B::operator X is not
   considered is that it will never be evaluated as a potential
   candidate. [over.match.ctor] consideres those constructors and
   [over.ics.list] then for both constructors end up with "In all cases
   other than those enumerated above, no conversion is possible.".

This has nothing to do with the points of 16[over.best.ics]p4 though,
so the example appears to be irrelevant to me. In order to fix this, I
think the example should use {{b}}, and make X a non-aggregate
class, if the example was really supposed to demonstrate the last
bullet of 16[over.best.ics]p4.

Personally I also find it confusing that the comment says that B::operator X is not a candidate, even though it is the move/copy constructor of X that would immediately be affected by the rules, if I am not mistaken? But, I suspect that's more of a matter of taste.