You are downloading the Engine Technology AppXBundle file v2017.831.821.0 for Windows Phone. Engine Technology is a free and useful Books & Reference app: The appendix contains a description of engine technology. The application includes a handy ... You can now download the offline AppXBundle file to install & try it.
Download Locations for Engine Technology 2017.831.821.0 AppXBundle file
Note: To install it manually from an SD card, you should choose one of the server location above to get the offline Engine Technology AppXBundle file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.