Adds a button to Firefox that toggles HiDPI mode on and off. This will scale the whole browser (both web site content and the Firefox user interface), which is useful on high resolution displays where text would be too small to be read without scaling.
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How it works
fxdpi changes the layout.css.devPixelsPerPx setting. The default is 1.4 because this is what I prefer on my 14" full HD laptop screen. You can change this value in the addon settings.