from an AWS EC2 instance. This is a security measure designed to prevent SSRF (Server-Side Request Forgery) attacks.

In a real-world script, this URL is only the first half of the puzzle. You use the token generated by that URL to actually get your data. Here is the complete script "piece": # Step 1: Get the token (Your URL) TOKEN=$(curl -X PUT "http://169.254.169" \ -H "X-aws-ec2-metadata-token-ttl-seconds: 21600" # Step 2: Use the token to get metadata (The Result) "X-aws-ec2-metadata-token: $TOKEN"

The string you provided is a URL-encoded command used to retrieve an IMDSv2 (Instance Metadata Service Version 2) session token

curl -X PUT "http://169.254.169" -H "X-aws-ec2-metadata-token-ttl-seconds: 21600" 2. The Two-Step Authentication "Piece"