The schemas can be found in two locations:
The schema can be found at http://pineapple.dev.java.net/ns/plugin/agent_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-agent-plugin project. The jar file is named pineapple-agent-plugin-${version}.jar.
The schema can be found at http://pineapple.dev.java.net/ns/plugin/composite_execution_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-composite-execution-plugin project. The jar file is named pineapple-composite-execution-plugin-${version}.jar.
The schema can be found at http://pineapple.dev.java.net/ns/plugin/ssh_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-ssh-plugin project. The jar file is named pineapple-ssh-plugin-${version}.jar.
The schema can be found at http://pineapple.dev.java.net/ns/plugin/docker_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-docker-plugin project. The jar file is named pineapple-docker-plugin-${version}.jar.
The schema can be found at http://pineapple.dev.java.net/ns/plugin/git_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-git-plugin project. The jar file is named pineapple-git-plugin-${version}.jar.
The schema can be found at http://pineapple.dev.java.net/ns/plugin/infrastructure_1_0.xsd
The schema can be found in the root of the jar created by the pineapple-infrastructure-test-plugin project. The jar file is named pineapple-infrastructure-test-plugin-${version}.jar.