home-assistant.io/source/_includes/edit_github.html

{% assign url_parts = page.url | split: '/' %}
{% if page.hide_github_edit != true %}
<div class='edit-github'><a href='https://github.com/home-assistant/home-assistant.github.io/tree/current/source/{{ page.path }}'>Edit this page on GitHub</a></div>
{% endif %}