$ xscreensaver -verbose
xscreensaver 5.03, copyright (c) 1991-2006 by Jamie Zawinski <jwz@jwz.org>.
xscreensaver: initial effective uid/gid was me/chkpwd (1000/24)
xscreensaver: running as me/me (1000/1000); effectively me/chkpwd (1000/24)
xscreensaver: in process 12226.
xscreensaver: 12:30:57: running xscreensaver-gl-helper: No such file or directory
xscreensaver: 12:30:57: xscreensaver-gl-helper did not report a GL visual!
xscreensaver: 12:30:57: running xscreensaver-gl-helper: No such file or directory
xscreensaver: 12:30:57: xscreensaver-gl-helper did not report a GL visual!
xscreensaver: 12:30:57: running on display ":0.0" (2 Xinerama screens).
xscreensaver: 12:30:57: vendor is The X.Org Foundation, 10400000.
xscreensaver: 12:30:57: useful extensions:
xscreensaver: 12:30:57:   MIT Screen-Saver  <-- not supported at compile time!
xscreensaver: 12:30:57:   Shared Memory
xscreensaver: 12:30:57:   Double-Buffering
xscreensaver: 12:30:57:   Power Management
xscreensaver: 12:30:57:   GLX
xscreensaver: 12:30:57:   XF86 Video-Mode
xscreensaver: 12:30:57:   Xinerama
xscreensaver: 12:30:57:   Resize-and-Rotate
xscreensaver: 12:30:57: screen 0 non-colormapped depths: 24.
xscreensaver: 12:30:57: Xinerama layout:
xscreensaver: 12:30:57:   + 0/0: 1280x800+0+0
xscreensaver: 12:30:57:     1/0: 1280x960+0+0
xscreensaver: 12:30:57: selecting RANDR events
xscreensaver: 12:30:57: consulting /proc/interrupts for keyboard activity.
xscreensaver: 12:30:57: 1: xinerama vp: 1280x960+0+0.
xscreensaver: 12:30:57: 0: visual 0x23 (TrueColor,   depth: 24, cmap: default)
xscreensaver: 12:30:57: 0: saver window is 0x4000001.
xscreensaver: 12:30:57: 1: xinerama vp: 1280x960+0+0.
xscreensaver: 12:30:57: 1: saver window is 0x4000005.
xscreensaver: 12:30:57: selecting events on extant windows... done.
xscreensaver: 12:30:57: disabling server builtin screensaver:
xscreensaver: 12:30:57:  (xset s 0 0; xset s blank; xset s expose)
xscreensaver: 12:30:57: mouse is on screen 0 of 2
xscreensaver: 12:30:57: awaiting idleness.