docs-source/supplemental_ui/layouts/default.hbs (11 lines of code) (raw):
<!DOCTYPE html>
<html lang="en">
<head>
{{> head defaultPageTitle='Untitled'}}
</head>
<body class="hide-versions article{{#with (or page.attributes.role page.role)}} {{{this}}}{{/with}}">
{{> header}}
{{> body}}
{{> footer}}
</body>
</html>