What is the channel attribute in the JSD create customer request API endpoint for?

The Create customer request endpoint in the Jira Service Desk REST API has an option to pass a channel string attribute in the payload. The docs say:

(Experimental) Shows extra information for the request channel.

Passing any string seems to be accepted but I cannot find where that would be exposed in the UI or in the request-channel-type attribute (this still seems to be fixed to the few hard-coded values).

Does anyone know how this attribute works or where I can find additional information about it?