I’ll start with a warning Defining custom webhook events is not a feature supported out of the box in Ghost and if you modify
/core/server you are left on your own to maintain the changes compatible with the upstream
Now to the possible solution You can find a list of supported webhook events here. These events usually come from model layer and can be overriden/enhanced in the model itself..
So, if you are looking to add a custom event you’d (1) emit it like this from the place of interest, (2) would make sure webhooks listen for that event and (3) your webhook has that event name set as it’s
event property in the database (because there’s no UI to set custom event listeners, which you might wanna (4*) modify here in Ghost-Admin.
Hopefully this is enough guidance for you to figure out the rest. Good luck!