% pkgutil --expand lifesaver-1.1.pkg ./lifesaver
pkgutil(37305,0x11926a5c0) malloc: can't allocate region
*** mach_vm_map(size=255086697644032) failed (error code=3)
pkgutil(37305,0x11926a5c0) malloc: *** set a breakpoint in malloc_error_break to debug
[1] 37305 abort pkgutil --expand lifesaver-1.1.pkg ./lifesaver
Sometime you run in environment there you can't provide administrator user and password. For such environments you would use screensaver name.saver
file to install it only for local user. This is I'm trying to unpack your wallpaper.