protected Set<URI> loadMavenRepositories() {
        Set<URI> repos = new HashSet<>();
        repos.addAll(super.getMavenRepositories());
        repos.addAll(config.getPluginRepositories());
        return repos;
    }
@return the maven repositories to use when downloading plugins
manager/api/war/tomcat8/src/main/java/io/apiman/manager/api/war/tomcat8/Tomcat8PluginRegistry.java