The “quoted email” UI has not changed over the years. As society has shifted towards a mostly mobile-first outlook, the lack of change in this small feature has become more obvious. If you have a long email chain, the quoted email text becomes increasingly more difficult to read through. The goal of this concept design is to come up with a user interface that would make it easy and convenient to read through quoted emails within the Gmail app. In this example you simply tap on the button to expand the content to reveal the most recent quoted email attached to a reply. You can read it in full-width view. If there are subsequent quoted emails nested, you can expand them as you go. Just a clean, simple way of solving this problem.