This feature contains the optional KNIME plugin that incorporates
the functionality of the Weka data mining framework (version 3.7).
Extension 
KNIME Weka Data Mining Integration (3.7)
Included nodes & related workflows
Legal
Copyright by KNIME AG, Zurich, Switzerland
This plug-in uses libraries and the source code of the WEKA project
(http://www.cs.waikato.ac.nz/ml/weka/), which is copyrighted
by the corresponding owners.
Update site information
KNIME Analytics Platform 4.3 Update Site, Version 4.3.0
http://update.knime.com/analytics-platform/4.3
In case you can’t install the extension via drag & drop, please check that the update site is activated.