RPX abbreviation expansion?

Question

Does anyone know if RPX is an abbreviation for something or just a name?

Answer 1

This FAQ says:

What does RPX stand for?

Relying Party Accelerator. From the OpenID 2.0 specification, a Relying Party is ...

Answer 2

According to this site (no idea how credible) it is "Relying Party X".

Context - "...RPX takes advantage of this and provides a middleman for the user depending on which service they selected they would like to use to login. The name means Relying Party X"