Come with download protection for a large number of executable file types on Windows, Mac and Linux.
The team improved performance for SDK extensions or extensions using the SDK module loader.
This new version come with Guarani (gn) locale.
One of the good feature is WebM EME Support for Widevine on Windows and Mac but nothing about Encrypted WebM streams.
As you know the Encrypted WebM streams are encrypted at the block level with AES-128 CTR encryption.
The AES encryption takes way lesser processing time than decryption.
Last come with new two updates to keyboard shortcuts:
- set a preference to have Ctrl+Tab cycle through tabs in recently used order;
- view a page in Reader Mode by using Ctrl+Alt+R (command+alt+r on Mac);
About the new Firefox version 50.0 you can read here.