In much the same way that 23 links to the sexually-related 69, 17 links to 68, as in the phrase "Sixty-eight and I'll owe you one." usually said by someone who wants to receive but not give in this sense. (3x23=69, 17x4=68)
There is no specific syntax for the quote. It is recommended that it be limited to the ASCII printing characters, space, carriage return, and line feed. The quote may be just one or up to several lines, but it should be less than 512 characters.