Roundcube is a browser-based multilingual IMAP client with an application-like user interface. It provides full functionality you expect from an email client, including MIME support, address book, folder manipulation, message searching and spell checking. the following KB will explain you to get the email headers in Roundcube webmail interface.
Step 1: Log in with your account username and password
Step 2: Select the Roundcube Webmail client
Step 3: Double Click on the message to open it
Step 4: Click on the arrow on the far right side of the screen
This will display the E-mail message header in a drop-down window. Click again on the arrow to hide the information.
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