The second alpha release of the 4.5 series is available from the extended downloads page and also from our distribution directory.
Tor Browser 4.5-alpha-2 is based on Firefox ESR 31.3.0, which features important security updates to Firefox. Additionally, it fixes a regression which caused third party authentication credentials to remain undeleted and contains smaller improvements to the circuit UI and the security slider.
Here is the changelog since 4.5-alpha-1:
Update Firefox to 31.3.0esr
Update NoScript to 18.104.22.168
Update HTTPS Everywhere to 5.0developement.1
Update Torbutton to 22.214.171.124
Bug 13672: Make circuit display optional
Bug 13671: Make bridges visible on circuit display
Bug 9387: Incorporate user feedback
Bug 13784: Remove third party authentication tokens
Bug 13435: Remove our custom POODLE fix (fixed by Mozilla in 31.3.0esr)