Cognito AttributeMapping: why isn't there an argument for the name attribute, which is a standard one?

[Bozz95]

Working with custom attributes and Cognito UserPool I notices that the name attribute is a standard one for Cognito, as it follows the OpenID specifications.

But this attribute is not yet used as an argument for the AttributeMapping, which forces me to define it via the custom argument.
From what I read in the issue #26820 which shoul add the prefix custom: to the ones specified there, so why don't align the user pool default attributes with the ones used as arguments?