Every templated system email carries an invisible 1x1 tracking image with a unique token. When the recipient's mail app loads images, the image request reaches Sprwt, which increments Opens and records First Opened/Last Opened for that log entry. Limits to keep in mind:

• If the mail client blocks remote images (common on corporate mail and some mobile apps), no open is recorded even though the email was read.
• Some mail providers pre-load/proxy images for privacy or security scanning, which can record an open the person never made.
• Plain emails sent without a template (Type General) have no pixel and always show a dash.
• Forwarded copies still carry the same tracking image, so an open from a forward counts against the original entry.

Treat the Opened column as an indicator, not proof.