In this times with billions of SPAM and phishing mails, I think a feature to analyze email headers automatically / internal in eM Client is a state-of-the-art feature.
Currently, the function to display the headers is very hidden. At the very least, it should be more easily accessible, and there should be a configurable button to send the current header to a web analyzer.
The best solution, however, would be an internal analysis tool that immediately points out “oddities” and, for example, cross-checks the servers using the unforgeable IP address in the header.