He's becomes with three default replacers:
1. @PROJECT_VERSION@, substitutes this text for a Project pom.xml version (same as ${project.version}).
2. @VERSION_SCM@, substitutes this text for project last scm version.
3. @DATE_TIME@, substitutes this text for actual timestamp, with cool configurable java stuff.
You can specify included files (and excluded too) in ant style, like '**/*.java' or 'src/main/webresource/bottom*.xhtml'.
Any suggestion for new default 'substituters' and in plugin project are welcome!
See more in:
http://code.google.com/p/maven-substitute-plugin/