Thread Summary

The discussion revolves around the HTTP headers "Traceparent" and "Request-Id" and their presence in raw fetch requests but not in Angular's HttpClient requests.

Key points:

1. "Traceparent" is part of the W3C Trace Context standard for distributed tracing, while "Request-Id" is a non-standard header used for tracing purposes.
2. These headers are not inherently added by the fetch API but are likely injected by environment-specific instrumentation (e.g., Azure App Insights), tracing libraries (e.g., OpenTelemetry), or custom middleware/proxies.
3. Angular's HttpClient does not automatically add these headers.

Conclusion:
The presence of "Traceparent" and "Request-Id" headers in raw fetch requests is likely due to external factors such as environment-specific instrumentation or tracing libraries, which are not inherently part of the fetch API or Angular's HttpClient.