How is \Magento\Sales\Model\Order\Payment::addTransaction() implemented and used?

Context:

Implementation

Details:

Usages

1. \Magento\Sales\Model\Order\Payment::refund()

2. \Magento\Sales\Model\Order\Payment::registerRefundNotification()

https://github.com/magento/magento2/blob/ffea3cd/app/code/Magento/Sales/Model/Order/Payment.php#L772-L776

3. \Magento\Sales\Model\Order\Payment::_void()

https://github.com/magento/magento2/blob/ffea3cd/app/code/Magento/Sales/Model/Order/Payment.php#L1104-L1105

Details: How is \Magento\Sales\Model\Order\Payment::_void() implemented and used?

4. \Magento\Sales\Model\Order\Payment\Operations\AuthorizeOperation::authorize()

https://github.com/magento/magento2/blob/ffea3cd/app/code/Magento/Sales/Model/Order/Payment/Operations/AuthorizeOperation.php#L49-L50

5. \Magento\Sales\Model\Order\Payment\Operations\OrderOperation::order()

6. \Magento\Sales\Model\Order\Payment\Operations\RegisterCaptureNotificationOperation::registerCaptureNotification()