Where can I find documentation about Modello?

The Modello model descriptor is described and documented with Modello.

Is Modello really used anywhere?

Modello is used extensively in Maven. You can find examples of models:

• Maven's POM: the mdo file for this model is maven.mdo (Maven 4; the Maven 3 version is on the maven-3.9.x branch)
• Maven's settings: the mdo file for this model is settings.mdo
• Maven assembly plugin: uses both an assembly model and an assembly component model
• Doxia site model, the model behind site.xml