assembly.xml

<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"  
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
    <id>assembly</id>
    <formats>
        <format>tar.gz</format>
    </formats>
    <includeBaseDirectory>false</includeBaseDirectory>
    <fileSets>
        <fileSet>
            <directory>${project.build.directory}/</directory>
            <outputDirectory>.</outputDirectory>
            <includes>
                <include>${project.artifactId}-firefox-${project.version}.xpi</include>
                <include>${project.artifactId}-chrome-${project.version}.zip</include>
                <include>${project.artifactId}-opera-${project.version}.zip</include>
                <include>${project.artifactId}-safari-${project.version}.zip</include>
                <include>license.txt</include>
      	    </includes>
        </fileSet>
    </fileSets>
</assembly>