code: private boolean installOptionalExtensionDependency(ExtensionDependency extensionDependency, String namespace,
          List<ModifableExtensionPlanNode> parentBranch, Map<String, ExtensionDependency> managedDependencies,
          Set<String> parents)
      {
          // Save current plan
          List<ModifableExtensionPlanNode> dependencyBranch = new ArrayList<>();
  
          try {
              installMandatoryExtensionDependency(extensionDependency, namespace, dependencyBranch, managedDependencies,
                  parents);
  
              parentBranch.addAll(dependencyBranch);
  
              return true;
          } catch (Throwable e) {
              if (getRequest().isVerbose()) {
                  this.logger.warn("Failed to install optional dependency [{}] with error: {}", extensionDependency,
                      ExceptionUtils.getRootCauseMessage(e));
              }
          }
  
          return false;
      }
docs: Install provided extension dependency.
  
  @param extensionDependency the extension dependency to install
  @param namespace the namespace where to install the extension
  @param parentBranch the children of the parent {@link DefaultExtensionPlanNode}
  @param managedDependencies the managed dependencies
  @param parents the parents extensions (which triggered this extension install)
  @throws InstallException error when trying to install provided extension
  @throws ResolveException
  @throws IncompatibleVersionConstraintException