You are downloading the MyAnimelistRT AppX file v126.96.36.199 for Windows Phone. MyAnimelistRT is a free and useful Social app: Manage your animelist. ... You can now download the offline AppX file to install & try it.
Download Locations for MyAnimelistRT 188.8.131.52 AppX file
Note: To install it manually from an SD card, you should choose one of the server location above to get the offline MyAnimelistRT AppX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.