In Kibana > Advanced Settings, the SIEM UI strings should be clearer:

Suggested text (please feel free to suggest other improvements):

• Anomaly threshold
  Value above which machine learning job anomalies are displayed in the SIEM app.
  Valid values: 0 to 100.

• Elasticsearch indices
  Comma-delimited list of Elasticsearch indices from which the SIEM app collects events.

• Time filter refresh interval
  Default refresh interval for the SIEM time filter, in milliseconds.

• Time filter period
  Default period of time in the SIEM time filter.