Conceptually copy-list-initialization is the conversion of a compound value to a destination type. The paper that proposed wording and explained rationale already considered the term “copy” in “copy list initialization” unfortunate, since it doesn’t really convey the actual rationale behind it. But it is kept for compatibility with existing wording. A {10, 20} pair/tuple value should not be able to copy initialize a String(int size, int reserve), because a string is not a pair.
Explicit constructors are considered but forbidden to be used. This makes sense in cases as follows
struct String {
explicit String(int size);
String(char const *value);
};
String s = { 0 };
0 does not convey the value of a string. So this results in an error because both constructors are considered, but an explicit constructor is selected, instead of the 0 being treated as a null pointer constant.
Unfortunately this also happens in overload resolution across functions
void print(String s);
void print(std::vector<int> numbers);
int main() { print({10}); }
This is ill-formed too because of an ambiguity. Some people (including me) before C++11 was released thought that this is unfortunate, but didn’t came up with a paper proposing a change regarding this (as far as I am aware).