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First, you need to install the Alfresco Module Package (AMP) alfresco-indexer-webscripts-x.amp provided in the ManifoldCF distribution plugin folder (plugins/alfresco-webscript) : https://manifoldcf.apache.org/en_US/download.html.
Copy the amp file into the alfresco installation amps directory (/opt/alfresco/amps).
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