As noted, I monitor these forums, and so will come across problems with the PDF this way. You can also send any errata to the e-mail Keith provided. That’s probably the best place for it.
Fixed the noted typos: thanks! Leave it to me to have a poorly edited sentence in a sentence about sections your editor has marked as being foul.
The Mysterious Mr. Stengel is no doubt going to enter the lexicon of strange PDF lore. I have no idea where the fragment came from (I don’t even think I ever put it in my pasteboard), and it was found in two different places, as well. Already fixed for the next release.