+-----------------------------------------------------------------------
+
+ <xscreensaver-text />
+
+ This indicates that this screen saver displays text via the
+ "xscreensaver-text" program.
+
+ In the X11 version, this tag does nothing: the text-related
+ preferences are in the main Screen Saver Preferences window,
+ not in the per-display-mode preferences.
+
+ In the MacOS version, the text-related preferences appear
+ in this pane, and this tag emits those several controls.
+
+-----------------------------------------------------------------------
+
+ <xscreensaver-image />
+
+ This indicates that this screen saver displays images via the
+ "xscreensaver-getimage" program.
+
+ In the X11 version, this tag does nothing: the image-loading
+ and screen-grabbing-related preferences are in the main
+ Screen Saver Preferences window, not in the per-display-mode
+ preferences.
+
+ In the MacOS version, the image-related preferences appear
+ in this pane, and this tag emits those several controls.
+
+-----------------------------------------------------------------------
+
+ <xscreensaver-updater />
+
+ Where to position the "Check for Updates" options.
+ This is used on MacOS and ignored on X11.
+
+-----------------------------------------------------------------------
+
+ <video href="URL" />
+
+ A link to a Youtube preview of this screen saver.
+
+-----------------------------------------------------------------------
+
+ <hgroup>
+ [ ... <boolean>s ... ]
+ [ ... <number>s ... ]
+ [ ... <select>s ... ]
+ [ ... <string>s ... ]
+ [ ... <file>s ... ]
+ [ ... <vgroup>s ... ]
+ </hgroup>
+
+ A horizontal group of widgets/groups. No more than 4 widgets
+ or groups should be used in a row.
+
+-----------------------------------------------------------------------
+
+ <vgroup>
+ [ ... <boolean>s ... ]
+ [ ... <number>s ... ]
+ [ ... <select>s ... ]
+ [ ... <string>s ... ]
+ [ ... <file>s ... ]
+ [ ... <hgroup>s ... ]
+ </vgroup>
+
+ A vertical group of widgets/groups. No more than 10 widgets
+ or groups should be used in a column.
+
+ Since the default alignment of widgets is a column, the
+ <vgroup> element is only of use inside an <hgroup> element.
+