I’ve loaded a grey scale (gradual transition + steps into darktable); adjusted exposure to make sure the darkest and brightest steps were reported as pure black and pure white, respectively, then applied @Jean-Paul_GAUCHE’s and @sacredbirdman’s LUTs. Interestingly, the first produced a definite shift to pink; the second remained neutral:
The histogram’s tint has nothing to do with this, that started with a recent darktable update.