It would be interesting to add push API sources and sinks

More information here:

• https://developer.mozilla.org/en-US/docs/Web/API/Push_API
• https://w3c.github.io/push-api/
• https://flaviocopes.com/push-api/

Possible sources:

• https://w3c.github.io/push-api/#pushmessagedata-interface

From the diagram here: https://w3c.github.io/push-api/#sequence-diagram, it looks like the registration of a push subscription is done via a normal fetch (by sending the PushSubscription), which is already included as a sink function.