Created attachment 175569 [details] 1.25 was the default value, but my screen scalling was 100%, instead of 125% By default, Firefox installed with pacman has "1.25" value in "about:config" → "layout.css.devPixelsPerPx". After changing the default screen scalling from 125% into 100%, Firefox's didn't change its 1.25 value. "1.25" is not supposed to be the default value: https://support.mozilla.org/mk/questions/1378420 Is there a way of making Firefox scalling always match the system scalling?
Probably, but this is something that Firefox itself would have to do. The fact that it correctly finds the default value indicates that it's capable of this, but apparently it doesn't track it if it changes.