You are downloading the DigiDoc XAP file v126.96.36.199 for Windows Phone. DigiDoc is a free and useful Productivity app: DigiDoc is the first Windows Store app which allows you to sign and open digitally signed documents in BDOC 2.1 and DigiDoc 1.3 ... You can now download the offline XAP file to install & try it.
Download Locations for DigiDoc 188.8.131.52 XAP file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline XAP 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 DigiDoc XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.