Firefox 51.0
https://www.mozilla.org/en-US/firefox/51.0/releasenotes/
New
Users can view passwords in the save password prompt before saving them
Added a zoom button in the URL bar:
- Displays percent above or below 100 percent when a user has changed the page zoom setting from the default
- Lets users return to the default setting by clicking on the button
Improved video performance for users without GPU acceleration for less CPU usage and a better full screen experience
Firefox will save passwords even in forms that do not have “submit” events
Added support for WebGL 2, with advanced graphics rendering features like transform feedback, improved texturing capabilities, and a new sophisticated shading language
A warning is displayed when a login page does not have a secure connection
Added Georgian (ka) and Kabyle (kab) locales
An even faster E10s! Tab Switching is better!
Improved reliability of browser data sync
Remove Belarusian (be) locale
Changed
Updated to NSS 3.28.1
Use 2D graphics library (Skia) for content rendering on Linux
Re-enabled E10s support for Russian (ru) locale
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Available via internal updater: HELP / About Firefox