Some documentation links have changed and not all have redirects.
ie/
https://doc.nuxeo.com/display/nxdoc/escalation-service/ returns a 404, but https://doc.nuxeo.com/display/NXDOC/Variables+Available+in+the+Automation+Context redirects to https://doc.nuxeo.com/NXDOC/Variables+Available+in+the+Automation+Context
Links should be updated.