For example, if you enter y = x+-3 you will see this graph.
The two parts of this function are each labelled with two annotations. The upper annotation retains the ± character with a positive or negative arm message. This is how FX Graph reports functions when Replace +- on Display is OFF. The lower annotation, where the ± character has been replaced by either + or - as appropriate, is how FX Graph reports these functions with Replace +- on Display ON.