Form and render elements in Field Group 8

Primary tabs

Element machine name	Type	Class	Namespace	Description
field_group_accordion	FormElement	Accordion	Drupal\field_group\Element	Provides a render element for an accordion.
field_group_accordion_item	FormElement	AccordionItem	Drupal\field_group\Element	Provides a render element for an accordion item.
field_group_html_element	FormElement	HtmlElement	Drupal\field_group\Element	Provides a render element for a html element.
horizontal_tabs	FormElement	HorizontalTabs	Drupal\field_group\Element	Provides a render element for horizontal tabs.