You, as a user, can however instruct List Fields to operate in raw-mode. This will make List Fields do the following:
Below, you see a screenshot from List Fields after we have enabled the MIME support in List Fields's Startup preferences:
Compared to the List Fields screenshot in easy-mode, you now see multiple Body fields. Each Body field typically contain a separate MIME part, and in the screenshot above we look at the text/html part.
Notice how List Fields format and colorize the HTML in this part. If you want closer look at any part in List Fields, why not copy the content to the clipboard ?