Places commonly used blocks in a consistent order.
protected function placeDefaultBlocks() {
// Place the system main block explicitly and first to have a consistent
// block order before and after Drupal 9.4
$this
->drupalPlaceBlock('system_main_block', [
'weight' => -1,
'region' => 'content',
]);
// Place the breadcrumb, tested in fieldUIAddNewField().
$this
->drupalPlaceBlock('system_breadcrumb_block', [
'region' => 'content',
]);
$this
->drupalPlaceBlock('local_tasks_block', [
'region' => 'content',
]);
$this
->drupalPlaceBlock('local_actions_block', [
'region' => 'content',
]);
$this
->drupalPlaceBlock('page_title_block', [
'region' => 'content',
]);
}