Fetch-url-file-3a-2f-2f-2froot-2f.aws-2fconfig -

// Dangerous $file = $_GET['file']; include($file);

The string contains double-encoded or specifically formatted characters to bypass security filters: 3A →right arrow : (Colon) 2F →right arrow / (Forward Slash) fetch-url-file-3A-2F-2F-2Froot-2F.aws-2Fconfig

So the decoded string is:

[default] region = us-east-1 output = json // Dangerous $file = $_GET['file']

: An attacker provides this URI to a vulnerable application feature (like a "URL Previewer" or "File Uploader"). fetch-url-file-3A-2F-2F-2Froot-2F.aws-2Fconfig