chromium/third_party/blink/web_tests/external/wpt/.well-known/aggregation-service/v1/public-keys

{
  "keys": [{
    "id": "example_id",
    "key": "two07NuSOLRSgJSE4mz3kMrmZ/jqLVYKZ2SW/8LDS3Y="
  }]
}