We use a lot of dynamic content in our emails. When we are sending sample emails to the team for proofreading, there isn't an easy way to to see which segment each test emails belongs to. It would be great to have something in the sample email which would let you know which segment it is, so we can easily identify where we need to go back and make changes.
For example if we had our dyanmic content segmentation by country, maybe the subject line could say "TEST - United States | Subject Line" or "TEST - Canada | Subject Line" so we knew which version was which.