When making a deployment, any kind of resource can be added to the deployment builder. However, some resources are treated specially since there is a dedicated deployer for them (e.g. .bpmn files become a ProcessDefinition in the API). For unaware Users it is an easy mistake to name a resource differently, resulting in no deployed process definition (see for example https://forum.camunda.org/t/deploy-bpmn-files-with-java-api-fails/1437). In this case, the API gives no clue what is wrong.

We should document (e.g. in the DeploymentBuilder's Javadoc) which resource name endings trigger which deployer (BPMN, CMMN, DMN).