Zero ohm resistor tolerance?
If you look at a "proper" data sheet (example: http://www.yageo.com/documents/recent/PYu-RC0603_51_RoHS_L_4.pdf) you'll usually find that the zero ohm resistor is defined separately using something like &lt; 0.05R.

In this case, you're looking at a more or less automatically generated set of data which is probably more relevant to the other resistors in the range.  Multicomp in this case refers to multiple sources so the parts could be coming from anywhere; the data in this case is fairly general and is most likely the lowest common denominator for a variety of alternative devices.