web-server/data/release/security/role/default/roles.xml

<?xml version="1.0" encoding="UTF-8"?>
<roleRegistry version="1.0" xmlns="http://www.geoserver.org/security/roles">
    <roleList>
        <role id="ADMIN"/>
        <role id="GROUP_ADMIN"/>
    </roleList>
    <userList>
        <userRoles username="admin">
            <roleRef roleID="ADMIN"/>
        </userRoles>
    </userList>
    <groupList/>
</roleRegistry>