There is a month old open issue in the maven plugin repository regarding support for other xtendm3 extensions types that has not feedback from infor.
https://github.com/infor-cloud/xtendm3-maven-plugin/issues/4
As it is now, the plugin does not work with APIs unless one of the non-master branches support it. This also means you have to install the plugin locally to use in a project. It's a great tool, so I hope infor intends to continue provide updates.
