To generate POMs with resolved information (e.g. version numbers) to check the values that the Release Plugin will use, set the property generateReleasePoms to true. Resolved values will be saved in release-pom.xml.
mvn release:prepare -DgenerateReleasePoms=true
This relies on release.properties being present from a previous release preparation. If this is not the case, you need to give the goal the name of the URL and optional tag to perform the release from. For example:
mvn release:prepare -DgenerateReleasePoms=true -DconnectionUrl=scm:svn:https://svn.apache.org/repos/asf/maven/plugins/tags/maven-release-plugin-2.0
After the release is complete, the release.properties and other release files will be removed from the checkout.