+ -w **DATE**::
+
+The wayback machine. Build the system using Debian archives from the specified
+date. Valid date formats are yyyymmddThhmmssZ or simply yyyymmdd. To learn
+which snapshots exist, i.e. which date strings are valid, simply browse the
+lists on http://snapshot.debian.org/. If there is no import at the exact time
+you specified you will get the latest available timestamp which is before the
+time you specified.
+This option is useful especially for release and debugging builds - for example
+if you know that the Debian archive was in a good state on a specific date but
+you want to build it on another day in the future, where the archive might not
+be as needed anymore. Please be aware that this is restricted to the plain
+Debian repositories only, as referred to in /etc/apt/sources.list.d/debian.list
+(so neither the Grml repositories nor any further custom ones are affected by
+the wayback machine).
+