getPathForFieldBlock example

// Both the content type created before and after Layout Builder was     // installed is still using the Field UI.     $this->drupalGet('admin/structure/types/manage/before/display/default');
    $assert_session->checkboxNotChecked('layout[enabled]');

    $field_ui_prefix = 'admin/structure/types/manage/after/display/default';
    $this->drupalGet($field_ui_prefix);
    $assert_session->checkboxNotChecked('layout[enabled]');
    $page->checkField('layout[enabled]');
    $page->pressButton('Save');

    $layout_builder_ui = $this->getPathForFieldBlock('node', 'after', 'default', 'body');

    $assert_session->linkExists('Manage layout');
    $this->clickLink('Manage layout');
    // Ensure the body appears once and only once.     $assert_session->elementsCount('css', '.field--name-body', 1);

    // Change the body formatter to Trimmed.     $this->drupalGet($layout_builder_ui);
    $assert_session->fieldValueEquals('settings[formatter][type]', 'text_default');
    $page->selectFieldOption('settings[formatter][type]', 'text_trimmed');
    $assert_session->assertWaitOnAjaxRequest();