To extract email headers from Thunderbird:
- Double-click the message to open it in a separate window.
- From the View menu, select Headers > All.
- Click the Forward button to forward the email to a third party.
- Do one of the following:
- View the message as is (with full headers) to the required address, or:
- Select the header and copy and paste it into a new message.
- Copy and paste the header into the Header Analyzer, and click Analyze Header.