Location-Scale Family
A location-scale family has the form
$$F(x) = F_0\left(\frac{x-\mu}{s}\right),$$where $\mu$ is a location parameter and $s > 0$ is a scale parameter. In a QQ-plot against $F_0$, data from a location-scale family should follow an approximate straight line with intercept $\mu$ and slope $s$.
This is why QQ-plots can detect both location shifts and changes in spread.