The first example for Initializer-List Constructors doesn't seem right. Specifically, the two uses of the range for loop:

for (auto value : args) ...

for (auto value : mSequence) ...

As these are, the copy constructor is called and then the value is throw away, right?

Earlier in the page there is the NOTE: For performance reasons, it is best to pass objects by const reference instead.

Wouldn't it be better for the two range-for examples be const references?

for (const auto& value: args) ...

for (const auto& value : mSequence) ...