After Windows Photo 10 leaks build 10123 on last week, a screenshot was also leaked by the Russian leaker WZor that reveals them notes release of the new build, confirming some of the changes Microsoft is planning for Windows 10.
In this build there are new applications for music and video.
"Music Preview and Video Preview have been replaced with new ones. "These new applications are now the default file handlers for the respective media file types," Microsoft said in a statement, confirming that it has completed application development.
As you know Windows 8 has its own standalone PDF viewer application. With Windows 10, that's about to change. His replacement Internet Explorer, Edge, at Windows 10, will become the default PDF viewer. Thus the Windows PDF viewer application Reader έχει αφαιρεθεί από το νέο λειτουργικό system.
However, if you still need it, you can install it from Windows 10 store.
The next WindUws 10 preview build 1012x will probably be officially released by the end of the month.
See the release notes.