FYI: I just found that this was also announced on Wikibooks mailing list:
http://lists.wikimedia.org/pipermail/textbook-l/2010-September/001572.html

jeluf wrote:

Your change has been completed.
Please reopen this ticket if anything went wrong.

The following configuration settings have been changed:

Index: InitialiseSettings.php

• InitialiseSettings.php (revision 2029)

+++ InitialiseSettings.php (working copy)
@@ -8638,6 +8638,11 @@

	'metawiki' => array( NS_MAIN, NS_TALK, NS_USER, NS_USER_TALK, NS_PROJECT, NS_PROJECT_TALK, NS_MEDIAWIKI, NS_MEDIAWIKI_TALK, NS_HELP, NS_HELP_TALK, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 200 ),

),

+'wmgCollectionHierarchyDelimiter' => array(
+ 'default' => false, // false == don't overwrite the extension's default settings
+ 'wikibooks' => '/',
+),
+
'wmgUseSpamBlacklist' => array(

'default' => true,
'private' => false,

You can find the entire config file at
http://noc.wikimedia.org/conf/highlight.php?file=InitialiseSettings.php

Thank you JeLuF!!