Intro

I use several three-monitor setups and one of the setups has a large TV-size screen as the monitor. I typically put my browser instances over there and need to shrink them to a more zoomed-out level to make websites usable at that size. The answer was to change the layout.css.devPixelsPerPx in the about:config¹. I changed mine to 0.8, which was equal to about the 80% zoom level which works for me. Because my workflow involves preferring new windows to tabs², this solution fit the problem nicely.

Note that this isn’t exactly the same as C-scroll, because it also changes the size of the text in your tab bar, for better or worse.

Footnotes

¹ The answer for the Firefox about:config came from https://support.mozilla.org/en-US/questions/963759

² New-windows-as-buffers shown at https://tech.toryanderson.com/2021/04/06/firefox-address-in-titles-for-exwm/