You are downloading the Extreme Music XAP file v18.104.22.168 for Windows Phone. Extreme Music is a free and useful Music app: ****WP 8.1 version is here****This version is only for Windows Phone 8. Search "Extreme Music" in the store for the WP 8.1 version.The ... You can now download the offline XAP file to install & try it.
Download Locations for Extreme Music 22.214.171.124 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 Extreme Music XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.