I am viewing a PDF file within the browser, Firefox 85, on Windows 10. I am following this webpage to make 120% zoom available: https://support.mozilla.org/en-US/questions/1201469 However, when I look at the zoom levels shown by toolkit.zoomManager.zoomValues, I already see the zoom level I want: 120% (showing as 1.2 in the list). Unfortunately, 120% doesn't show in the list of zoom levels in my Zoom pulldown menu. The list jumps from 100% to 125%. If I use "+" or "-" (either on the keyboard or the icons at the top of the page), the zoom jumps from 110% to 130%. I am confused by two things. 1. The +/- zoom levels don't match the zoom levels in the pulldown menu.. 2. Neither match the zoom levels shown by toolkit.zoomManager.zoomValues How do I definitively control my zoom levels?