Maven currently distributes xpp3, baked into the plexus utilities JAR.
However, StAX is a comparable standard that has multiple implementations, including being distributed in Java 6. Much of the toolchain has already been updated to handle it, such as Modello.
This could serve as an equally performant replacement while removing the maintenance burden of our own XML parser.
Replace the xpp3 parsers in the maven-model with the stax generated parsers.
With the proper separation of plugins, this will not impact plugins that use the xpp3 based parser.
Note that to achieve the benefit of reducing the distribution size, plexus and plexus utilities will need the same modification.