Magento2 breadcrumbs on a product page

By default Magento2 does not show the product page breadcrumb.

Refer to this answer by nuwas for a decent breadcrumb implementation.

https://magento.stackexchange.com/questions/225370/magento-2-2-4-breadcrumbs-do-not-show-on-product-pages-when-default-navigation

If there is multiple categories or sub categories, it may not order the navigation correctly,  fix that by ordering by level, it could be improved further by also ordering by position.

    $cats = [];
                foreach ($breadcrumbCategories as $category) {
                    $cats[]=['level' => $category->getData('level'),
                        'position' => $category->getData('position'),
                        'name' => $category->getName(),
                        'url' => $category->geturl(),
                        'id' => $category->getId()];
                }
                usort($cats, function ($item1, $item2) {
                    return $item1['level'] <=> $item2['level'];
                });

                foreach ($cats as $category) {
                    $catbreadcrumb = array("label" => $category['name'], "link" => $category['url']);
                    $breadcrumbsBlock->addCrumb("category" . $category['id'], $catbreadcrumb);
                    $title[] = $category['name'];
                }