Magento 2.1: Get Breadcrumb Array

I know this is a rather old question, but since I ran into sort of the same issue I thought I'd share my answer:

If you want to call it in a custom template, I suppose you should make a module first and create a custom Block class. Then use dependency injection to get the Helper\Data from the Magento_Catalog-module, as follows:

<?php
namespace Name\Module\Block;

use Magento\Catalog\Helper\Data;

class CustomBreadcrumbBlock {

    protected $catalogData;

    public function __construct(
        Data $catalogData
    ) {
        $this->catalogData = $catalogData;
    }

    public function getBreadcrumbPath() {
        return $this->catalogData->getBreadcrumbPath();
    }
}

Then you should be able to call $block->getBreadcrumbPath() in your custom block template, which will return an array of your breadcrumb path.

You can also just extend the Magento\Catalog\Block\Breadcrumbs class when you make your custom block class. To use the getBreadcrumbsPath() method you write a public method to access the protected object $catalogData to use Data::getBreadcrumbsPath() (i.e. getCatalogDataHandler()).

Then in phtml-file you can do like $block->getCatalogDataHandler()->getBreadcrumbsPath().

The getBreadcrumbsPath() method gives you an assoc array with some category id as key and link and label in value-array so perhaps its a good idea anyway to write a public block-method that gives you exactly what you want. I just needed the id for the top level category.

CODE:$breadcrumbsBlock = $resultPage->getLayout()->getBlock('Magento\Catalog\Block\Breadcrumbs');