The last remaining shill technique (with everything else being provably false/agitprop) is the "non-falsifiable claim".

The term "the files" is used so persistently precisely because it's something too vague to be proven or disproven from existing. Numerous documents and data that could be called "files" have already been released, others are under seal by Democrat judges (you know where you send your angry letters, sweatie), so they prey on that abstract idea that there could always be just ONE more "the files" that didn't get released that will surely prove every imagined claim and say exactly what they want by way of implicating all the bad meanie no-no-heads they don't like (mainly the orange one).
Because no such document can be proven to exist or even be suspected of existing by any non-anonymous source, this imaginary document can be alluded to be the one intentionally hidden/suppressed.

The entire shill argument can essentially be reduced to "Why don't you just manufacture and release a document that says I win and you lose?".

tldr it's bertrand russell's teapot