# Why do software packages sometimes use the function $0.5+|AUC-0.5|$ when the AUC is less than $0.5$?

I noticed that software packages sometimes use the function:

.5 + abs(AUC-.5)

when the AUC is less than $0.5$. In other words, it has:

$$0.5+|AUC-0.5|$$

as a way to report AUC's under 0.5. Is this just a result of an AUC under $0.5$ being a worthless predictor and is the function above just reversing the labels to whatever prediction scheme is used to calculate the AUC? Thanks.