Among the Firefox 25 changes include the find/search bar no longer being shared between tabs, resetting Firefox no longer clears the browser session, CSS3 background-attachment:local is now supported, and many new ES6 (ECMAScript 6) functions have been implemented.
Among the newly-implemented ECMA Script 6 functions include new math functions, Map#forEach and set#forEach, Array.of, Number.parseInt, and Number.parseFloat. More details on the current Firefox / Gecko engine support for ECMA Script 6 can be found via developer.mozilla.org.
Firefox 25 for Android meanwhile has new guest browsing support, mixed content blocking has been enabled, add-ons can now add indicators to the URL bar, and there's developer / CSS3 / HTML5/ ECMA Script changes similar to Firefox 25 for the desktops.
The Mozilla Firefox 25.0 release for major operating systems can be downloaded from this FTP directory while awaiting the official announcement from the Mozilla crew on Tuesday.