A webhook we stopped sending

An outbound webhook with two subscribers, both of whom had stopped consuming it and neither of whom had said so.

  deliveries attempted, last 90 days:  41,208
  delivered (2xx):                     41,208
  and the subscriber endpoints:
    integrator-A  returns 200 and discards. confirmed
                  by asking.
    integrator-C  returns 200 from a generic catch-all
                  route. the handler was removed in
                  2024.

both were answering successfully and doing nothing,
which is exactly what our own supplier integration had
been doing to us.

Delivering successfully to somebody who discards it is indistinguishable from delivering usefully, from our side, which is the same asymmetry as the supplier case seen from the other end. The only way to know is to ask, and asking two integrators took one email each.