You are downloading the Windows Previewer Beta APPX file v2015.123.1714.1407 for Windows Phone. Windows Previewer Beta is a free and useful Productivity app: The update provisioning application allows users to get early access to the latest Windows Phone updates for the purposes of providing feedback to ... You can now download the offline APPX file to install & try it.
Download Locations for Windows Previewer Beta 2015.123.1714.1407 APPX file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline APPX File To Install It Any More.
To try to install it manually from an SD card, you should choose one of the server location above to get the offline Windows Previewer Beta APPX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.