<p>The name of the partner or external event source. You cannot change this name after you create the channel. A maximum of one channel is allowed per source.</p> <p> A source can be either <code>Custom</code> for all valid non-Amazon Web Services events, or the name of a partner event source. For information about the source names for available partners, see <a href="https://docs.aws.amazon.com/awscloudtrail/latest/userguide/query-event-data-store-integration.html#cloudtrail-lake-partner-information">Additional information about integration partners</a> in the CloudTrail User Guide. </p>