When reading GMail on Safari, I don't see headers

This started today. Probably some Gmail config issue, but I can't find any setting.

I see the email body, but no header information (To:, From:, CC:, Subject:, etc.)

Perhaps there was some shortcut key I bumped my finger into?

Answer: I got several emails from my wife with no body but subjects that went on forever. The subject header is not introduced with "Subject:" and it looks pretty indecipherable. I'll go try to delete this.