What are RadzenHeader and body

I am looking at some generated code

<RadzenHeader>
  <ChildContent>
    <div class="row justify-content-start align-items-center">
      <div class="col-md-6 d-flex align-items-center">
        <RadzenSidebarToggle Click="@SidebarToggle0Click">
        </RadzenSidebarToggle>
        <RadzenLabel Text="SamsonRadzen">
        </RadzenLabel>
      </div>
      <div class="col-md-6 text-lg-right">
      </div>
    </div>
  </ChildContent>
</RadzenHeader>

What are the special Radzen versions of the body, headers bringen to the table?

Also looking at this code. Is it only in the paid version?

<RadzenSidebar @ref="sidebar0">
  <ChildContent>
    <RadzenPanelMenu style="height: 100%">
      <ChildContent>
        <RadzenPanelMenuItem Text="Customers" Path="customers">
        </RadzenPanelMenuItem>
        <RadzenPanelMenuItem Text="Customer Contacts" Path="customer-contacts">
        </RadzenPanelMenuItem>
        <RadzenPanelMenuItem Text="Customer Contact Maps" Path="customer-contact-maps">
        </RadzenPanelMenuItem>
        <RadzenPanelMenuItem Text="Customer Contact Types" Path="customer-contact-types">
        </RadzenPanelMenuItem>
        <RadzenPanelMenuItem Text="Customer Raws" Path="customer-raws">
        </RadzenPanelMenuItem>
        <RadzenPanelMenuItem Text="Customer Types" Path="customer-types">
        </RadzenPanelMenuItem>
      </ChildContent>
    </RadzenPanelMenu>
  </ChildContent>
</RadzenSidebar>