We need to display a computed summary of submitted information on both the submission preview page and in e-mails that are sent out.
I'd expect this is a common usecase and wanted to check if i'm missing something obvious before cobbling something together (and documenting that and leading others astray!)— like figuring out if computed twig elements can be excluded from the original form, and if the same computed twig elements can be pulled into the email handler easily.
Thanks for any assistance!
(Edited body and title: clarified that this need is for the submission preview page, not the Webform 'confirmation' page)