If that's how it is, I really, really don't like the mysterious, badly defined word "webhook".

My company offers a way to configure a default or overwrite-per-individual-process callback url for... at least 10 years now. It's the primary way for us to communicate our results to our direct customers and it's two database columns, packing some results in a JSON object, an SNS/SQS queue and executing a HTTP request. In any case, it's very primitive and nothing worth getting its own name and countless blog posts written about.