score:8
It refers to the entire book, but especially the Book of Signs, John 1:19 - 12:50. (As with your note about arbitrary chapter beaks, notice that this doesn't align with the beginning of a chapter.) There are seven miracles or signs that John uses to establish Christ as the Son of God
Some add the Crucifixion, Resurrection, and/or the miraculous catch of fish. However, the list of seven is fairly common, a nice biblical number, and has some interesting theology developed from it.