A BreadcrumbList is an ItemList consisting of a chain of linked Web pages, typically described using at least their URL and their name, and typically ending with the current page.
breadcrumbs.html
to your site's _includes
folder{% include breadcrumbs.html path=page.path title=page.title %}
<!-- comments -->
If you don't know how includes work, go to Jekyll includes on Jekyll official website.
Jekyll-Breadcrumb-Microdata automatically and dynamically generates breadcrumbs for your website. Together with breadcrumbs, structured data in Microdata format are also generated.
Tested with Google Structured data
Good for GitHub Pages