deploy profile

In addition to main POM, for open source projects pl.wrzasq.parent:parent-opensource defines deploy profile (to use as mvn -P deploy), which performs deployment to public repositories.

Plugins

org.apache.maven.plugins:maven-gpg-plugin

Bound to phase verify, creates a certificate, which is needed to publish project artifact to staging repository.

org.sonatype.plugins:nexus-staging-maven-plugin

Open source projects are configured to be deployed into central OSS Sonatype repository.