I am on Linux, with font defaults on 15px. I have also set the minimum font size in firefox to 15, yet all content of webpages and even the settings menu (which I've noticed ignores the font size settings entirely) is minuscule by comparison - I found the font sizes of the adress bar (respecting system font size of 15) matching webpages scaled to 140% or minimum fonts set to 22.

Changing the `layout.css.devPixelsPerPx` scales the adress bar too, aside of just scaling all elements, not text.