I'm working on a Thinkpad T480s, which has a WQHD (2560x1440) 14" display. This makes for very small fonts in Firefox and the window manager (Xfce).
In principle, I could set the
layout.css.devPixelsPerPx setting in Firefox and manually set the window manager font size etc. However, I also have a 27" WQHD external monitor. And this means that all these settings (window manager, Firefox) would make the fonts good on one but bad on the other screen.
So my question seems to be the following: How can I set different DPI values for my different screens, and have all applications (i.e., Firefox) respect these?
I should add that apparently, there once was a AutoHiDPI extension for Firfox, but it seems to be gone and I cannot find it.