You are downloading the Maestro APPX file v2015.318.456.4670 for Windows Phone. Maestro is a free and useful Productivity app: **FREE for the first 24 hours only!** Introducing Maestro: a better mail client for Windows Phone. With unique features like account ... You can now download the offline APPX file to install & try it.
Download Locations for Maestro 2015.318.456.4670 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 Maestro APPX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.