You are downloading the 6sec XAP file v126.96.36.199 for Windows Phone. 6sec is a free and useful Social app: 6Sec is the only full Vine client app (including upload feature) for Windows Phone. 6Sec for Vine is the best way to see and share life in motion. ... You can now download the offline XAP file to install & try it.
Download Locations for 6sec 188.8.131.52 XAP file
Note: To install it manually from an SD card, you should choose one of the server location above to get the offline 6sec XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.