Oh, I see. You mean, how does 2600 authenticate it? Probably they don’t. In fact, now that you mention it, I have no idea how that would work. (Except as a publicity/anti-Trump statement by 2600 et al, for which it serves the purpose the moment they ask regardless of whether anyone takes them up on it.)
From a purely forensic standpoint, you’d have zero confidence initially about anything that landed in your inbox, and very little way to improve that. Even if you convened a blue-ribbon panel of investigative journalists and tax attorneys, it might still be difficult to determine whether it was a fake, or whether it was an accurate return that Trump lied on.
And yeah, Trump could just scream FAAAAAAAAAAAAAAKE even if they weren’t.
