This should either be public or api-supported. Perhaps it should be public/api but
at least for now I will resolve by removing the annotation
* form (Contribution_Main) available from the others in the same flow
* (Contribution_Confirm, Contribution_ThankYou).
*
- * @api This function will not change in a minor release and is supported for
- * use outside of core. This annotation / external support for properties
- * is only given where there is specific test cover.
- *
* @return string[]
*/
protected function getSubmittableFields(): array {