Restore default zoom level for websites in Firefox. Firefox browser offers Zoom Controls, you can find them in the menu. Or you can use Ctrl ++ to Zoom in or Ctrl — to Zoom out of a website and Ctrl + 0 to reset. To improve the readability, you can increase the text size or set a custom zoom level for a web page.
Firefox remembers the specific zoom level you’ve set for individual websites in the browser and always shows those pages at that zoom level. Wondering how to restore default Zoom value for those sites, i.e. 100%, continue to read on.
Reset all websites zoom level to default in Firefox browser
2. Change the preference value of browser.zoom.siteSpecific to ‘false’.
Side tip: If you want to Zoom only text on a web page, but not the images, press Alt View> Zoom > Zoom Text Only.