_user field on webhook events was intended to make it easier to match up which events were sent to which of the recipient's users. In hindsight, this is not terribly useful, and duplicates what the
state parameter is supposed to be doing.
We are deprecating this field, and it will be removed from API results on the 11th of October 2021.
This change will affect the following endpoints:
It will not affect regular webhook event payloads, which will not change.