I recently bought a keyboard and mouse for my tablet and pale moon is the only app that has inverted scrolling. Scrolling up causes the page to move down and scrolling down moves the page up.
I was able to find a couple posts about inverting the scroll in firefox, but changing the setting does nothing in pale moon.
Setting 'mousewheel.default.delta_multiplier_y' to -100 in about:config is supposed to invert the scrolling direction.