Sharepoint - Textual resolution of [Current User] and [Me]

The [Me] reference is a type of function in SharePoint / Office. Use the following link to see the official documentation on Formulas and Functions. This isn't exactly the side-by-side comparison you are looking for but, it does detail things fairly well.

Specifically speaking, if you go into Information | Me Function you will see what they have listed to explain how [Me] works. They explain that "...returns the current user name." as well.