This is the (RFC 3927) reserved for cloud metadata services. When an attacker sends you a webhook URL that looks like http://169.254.169.254/metadata/identity/oauth2/token , they aren't trying to send you a friendly notification. They are trying to trick your server into stealing its own cloud identity tokens.
A webhook URL, also known as a callback URL or webhook endpoint, is a URL that an application or service uses to send notifications or updates to another application or service. It's essentially a callback function that receives data from a server. This is the (RFC 3927) reserved for cloud metadata services
AWS EKS Credentials Exposure via Server Side Request Forgery in ... This is the (RFC 3927) reserved for cloud metadata services