Security Information and Event Management. The platform that ingests logs and runs detection rules.
A SIEM is the central platform a security team uses to ingest logs from across the estate, correlate events across data sources, run detection rules, raise alerts and store events for incident-response queries. Common SIEMs include Splunk, Microsoft Sentinel, Google SecOps (formerly Chronicle), Elastic and OpenSearch.
CloudSigma's output Sigma rules convert to all five of those dialects via the pySigma toolchain. DCV's coverage data is SIEM-independent: the underlying mappings are between cloud-service findings and ATT&CK techniques.