https://www.w3.org/WAI/WCAG22/Understanding/accessible-authentication-minimum

...の「Two-factor authentication systems (verification codes)」にはこう書かれている。

「Evaluating whether or not the code can be seamlessly transferred from the secondary device to the primary device is outside of the scope for this Success Criterion. (中略) Evaluating this criterion therefore only requires verification that the web content does allow pasting the clipboard content in the related authentication challenge field.」