Sets the port on which the application used to transfer files to and from the guest will be listening on.
When file_transfer_client is scp, this is by default 22:
variants: - @Linux: file_transfer_client = scp file_transfer_port = 22
And for rss, the default is port 10023:
variants: - @Windows: file_transfer_client = rss file_transfer_port = 10023:
No other documentation currently references this configuration key.