A Maven 2/3 plugin to store credentials from settings.xml and security-settings.xml into properties where they can be used by other plugins and/or Java code.
Please see the Project Page.
There's also the Issues page.
This plugin is also something of a testbed for Maven plugin testing strategies. I'm using Cucumber-JVM to drive standard JUnit-style tests as well as Maven Verifier integration tests. I'm also using the Maven Invoker Plugin for standalone functional tests.