In PP software (I happen to use LR) there are two sliders in the WB controls: temperature and tint. In a two dimensional slice taken from a colour space, the (black body) temperature can be represented by a curved line (i.e. a surface in the three dimensional space) running from the red tones to the blue ones (I think this is properly called the Planckian locus). When we adjust the temperature controller we move the representation of the image along this line or surface. The edges of the colour space approximately orthogonal to this line are magenta (mid-way between red and blue) and green (the third primary). Hence, when we use the tint slider we are moving the line/surface toward magenta or green - only roughly because I think that the direction of movement changes as we move along the locus.