Does mediasoup-demo example with gstreamer supports rtcp feedback?

Hi there! I was recently looking for information about correct setup of gstreamer and mediasoup with rtcp feedback support. And then i found this example
And as i can see this pipeline doesn’t use the udpsrc at all (usually it uses for receiving some data in gstreamer). When i check communicating between mediasoup and gstreamer i found out that mediasoup sends RR (rtcp receiver report) to the rtcp port it connected previously. for example

myPlainTransport.connect({ ip: RTP_IP, port: RTP_PORT, rtcpPort: RTCP_PORT })

But does feedback really works without udpsrc that can receive and process RR messages from mediasoup?