maven.multiproject.includes property.
 2. it works without problems only for projects with relative paths, e.g., from
 one CVS repository.. for projects from multiple SCM repositories it's harder
 to maintain the same relative links on all developer computers.
 not sure the unified source directory structure addresses this issue.

 Properties

 maven.user.config.dir (system,default=${user.home}/.m2)

        <field>
          <name>subscribe</name>
          <version>3.0.0+</version>
          <description>
            The email address or link that can be used to subscribe to
            the mailing list.  If this is an email address, a
            {@code mailto:} link will automatically be created
            when the documentation is created.
          </description>
          <type>String</type>
        </field>

                    it.hasNext(); ) {
                URL url = it.next();
                List<String> lines;
                try (InputStream is = url.openStream();
                        BufferedReader reader = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8))) {
                    lines = reader.lines()
                            .map(String::trim)

/**
 * The Exception class throw by the {@link Lookup} service.
 *
 * @since 4.0.0
 */
@Experimental
public class LookupException extends MavenException {

    public LookupException(String message) {
        super(message);
    }

    /**
     * @param message the message to give
     * @param e the {@link Exception}
     */
    public LookupException(String message, Exception e) {

        this.pluginDescriptor = pluginDescriptor;
        this.originalMessage = originalMessage;
    }

    /**
     * Ctor left for binary compatibility.
     *
     * @deprecated Use {@link #PluginConfigurationException(PluginDescriptor, String, Throwable)}
     */
    @Deprecated
    public PluginConfigurationException(

    /**
     * Returns the plugin context for mojo being executed and the specified
     * {@link Project}, never returns {@code null} as if context not present, creates it.
     *
     * <strong>Implementation note:</strong> while this method return type is {@link Map}, the
     * returned map instance implements {@link java.util.concurrent.ConcurrentMap} as well.
     *

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**
 * Access to {@link Type} registry.
 *
 * @since 4.0.0
 */
@Experimental
public interface TypeRegistry extends ExtensibleEnumRegistry<Type> {

    /**
     * Obtain the {@link Type} from the specified {@code id}.
     * If no type is known for {@code id}, the registry will
     * create a custom {@code Type} for it.

    /**
     * Gets the problems that were encountered during the settings building. Note that only problems of severity
     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link ToolchainsBuilderException}.
     *
     * @return the problems that were encountered during the settings building, can be empty but never {@code null}

 */
public interface MavenArtifactRelocationSource {
    /**
     * Returns {@link Artifact} instance where to relocate to, or {@code null}.
     *
     * @param session The session, never {@code null}.
     * @param result The artifact descriptor result, never {@code null}.
     * @param model The artifact model, never {@code null}.
     * @return The {@link Artifact} to relocate to, or {@code null} if no relocation wanted.
     */

        super(plugin, message, e);

        this.pluginRealm = pluginRealm;
    }

    /**
     * Ctor left for binary compatibility.
     *
     * @deprecated Use {@link #PluginContainerException(Plugin, ClassRealm, String, Throwable)}
     */
    @Deprecated
    public PluginContainerException(
            Plugin plugin, ClassRealm pluginRealm, String message, PlexusConfigurationException e) {