LM139 datasheet has this footnote for the input common mode voltage range parameter, which is specified as min = 0v, max = Vcc-1.5 V in the electrical characteristics table:
The upper end of the common-mode voltage range is Vcc-1.5 V, but either or both inputs can go to +30 V without damage.
So what does this mean? What's the point of the +30v part?