roslaunch automatically tab-completes any files with a .launch extension. In order for launch files that are mostly used as includes to show up on those listings, they are given a second extension .xml (which they actually are).
roslaunch automatically tab-completes any files with a .launch extension. In order for launch files that are mostly used as includes to not (edited) show up on those listings, they are given a second extension .xml (which they actually are).