Receiving Events

I want to understand how the traccar server notifies the web app that the server has received data from a device, especially location updates.

1. Does the web app rely on making api calls to get latest update from the server every second?
2. Does the web app use websockets to get l latest update for the server for devices changes?
3. Does the server sends the web app push notifications , to alert it that new data has arrived , so that the web app downloads?

1. No.
2. Yes.
3. No.