Template notations in magento

Question

I was working with the Algolia search module in Magento 2 and foud something like below in the template files. Can anybody let me know what this notation is called and where can I learn more about this notation.

<div class="algoliasearch-autocomplete-category">
                {{#categories_without_path}}
                <?php echo $block->escapeHtml(__('in')); ?> {{{categories_without_path}}} {{/categories_without_path}} {{#_highlightResult.color}} {{#_highlightResult.color.value}}
                <span>
                    {{#categories_without_path}} | {{/categories_without_path}} Color: {{{_highlightResult.color.value}}}
                </span>
                {{/_highlightResult.color.value}} {{/_highlightResult.color}}
            </div>

Thank you