This feature defines a mechanism that enables developers to declare a network error reporting policy for a web application via the `NEL` header. A user agent can use this policy to report encountered network errors that prevented it from successfully fetching requested resources. This is done through the common Reporting API.
Docs: https://w3c.github.io/network-error-logging/ https://w3c.github.io/reporting/ https://dcreager.net/nel/intro/