White Question Mark in Black Diamond

Question

We are all familiar with the white question mark inside of a black diamond (�) when there is an encoding issue. Does this 'character' have an offical name? Or is it only referred to as the 'white question mark inside of a black diamond'? What would that name be if it has one?

Answer 1

It's the Unicode REPLACEMENT CHARACTER.

Answer 2

It's called "Replacement Character". See the related Wikipedia page.

U+FFFD �​: "replacement character" used to replace an unknown or unprintable character.