Explain what a special prefix/suffix is

[rnveach]

https://google.github.io/styleguide/javaguide.html#s5.1-identifier-names

In Google Style special prefixes or suffixes, like those seen in the examples name_, mName, s_name and kName, are not used.

Can you please elaborate and explain what you deem to be a special prefix/suffix and update the guide with such definition and how the current list of examples violate it?
Is it referring to Hungarian notation or something else?

mName

Would any single letter before Name violate this as special, or are there some cases where it would be acceptable? Ex: eName

[jakub-bochenski]

To give some more concrete examples: the checkstyle template will not allow names like:

• xTransaction (for X-Transaction)
• eCommerce (for E-Commerce)

Are those prefixes the disallowed "special prefixes"?