This feature contains the Amazon Redshift JDBC driver which is distributed under a non-open source proprietary license. Installing this feature requires the KNIME Redshift Connector And Tools feature.
Extension 
KNIME Amazon Redshift Driver
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Copyright by KNIME AG, Zurich, Switzerland
Update site information
KNIME Analytics Platform 4.6 Update Site, Version 4.6.0
http://update.knime.com/analytics-platform/4.6
In case you can’t install the extension via drag & drop, please check that the update site is activated.