XAP is combination of 2 or more files which have .dll,.XAML and some resource files. In real .XAP is a compressed file for silverlight application. Now comes to the files it contains below is the list for the same:-
AppManifest.xaml
Compile assembly of silverlight project(.dll) file
Other resources of silverlight application.
Usualy Visual studio creates 2 files while creating project
(i)App.XAML
(ii)Page.xaml
