The author of that comment was incorrect though. Page 18 of the PDF shows that it was an arbitrarily hardcoded number encoded in a BigDecimal, has nothing to do

The author of that comment was incorrect though. Page 18 of the PDF shows that it was an arbitrarily hardcoded number encoded in a BigDecimal, has nothing to do with 16 bit integers. Furthermore the limit was 65*3*55... whereas the max 16-bit unsigned integer is 65*5*35, so the digits don't even match up. It's a cool hypothesis, and perhaps the person who hardcoded that number was even inspired by 2^16 - 1 in some way, but as the replies point out it doesn't really make much sense beyond an odd curiosity.