FM 8-01 Chapter 8 · Email and identity
Email header analyser
Trace the Received path of a message with delays per hop, and read its SPF, DKIM, DMARC and ARC results.
Local only Runs in your browser. Nothing you enter leaves this page.
In Gmail: Show original. In Outlook: File, Properties, Internet headers. In Apple Mail: View, Message, All Headers. Everything stays in this tab and is never written to the address bar.