From the OPA140 datasheet here: https://www.ti.com/lit/gpn/opa2140
Looks like they’re stating it as the reciprocal, so 0 would be infinite gain. So for a 10k load and 25 degrees C the 1/gain is typically about 0.15u/V or a gain of 6.7x10^6.
That’s 136dB which is quite a bit higher than the typical figure of 126dB over a wide common-mode voltage range.
Not sure why they’re stating it as negative, maybe aesthetics so up=positive, either polarity is okay- it depends on which input they are assuming to be connected to the signal input.