Where did this envelope come from?

When I got to the office this morning, I noticed something strange. There was a large manilla envelope placed atop a stack of papers I had left on my desk. We have departmental mailboxes so I don't think it is mail for me. Panjabe is quite the confused man at this point, let me tell you. No one could have gotten into my office to leave this envelope, the janitor and I have the only keys, and he is a trustworthy individual who would not leave mysterious envelopes for me. I suppose that bastard Dominic Jones could have, but he wisely does not enter my office after I told him I had deployed gene-specific biological weapons in my airspace designed to leave him as little more than a mass of slop.

That's a joke.

Maybe.

So I have no idea where this envelope came from, if it is intended for me, and if I should open it. It's clasped, not sealed, so if it contains anthrax or anything like that, I'm already doomed. It's too small to be a bomb. Hold on a second. I'm going to open it.

Corporate tax documents from the year 2004? But there wasn't even a PWF in 2004.

Now Panjabe is more confused than ever.