Element checkboxes

checkboxes =>

array:10 [
  "class" => "Drupal\Core\Render\Element\Checkboxes"
  "provider" => "core"
  "id" => "checkboxes"
  "#input" => true
  "#process" => array:1 [
    0 => array:2 [
      0 => "Drupal\Core\Render\Element\Checkboxes"
      1 => "processCheckboxes"
    ]
  ]
  "#pre_render" => array:1 [
    0 => array:2 [
      0 => "Drupal\Core\Render\Element\Checkboxes"
      1 => "preRenderCompositeFormElement"
    ]
  ]
  "#theme_wrappers" => array:1 [
    0 => "checkboxes"
  ]
  "#value_callback" => array:2 [
    0 => "Drupal\Core\Render\Element\Checkboxes"
    1 => "valueCallback"
  ]
  "#type" => "checkboxes"
  "#defaults_loaded" => true
]