You can access the active site via this.site and it returns the object System\Models\SiteDefinition current site definition.
{{ this.site.id }}
{{ this.site.name }}
{{ this.site.code }}
{{ this.site.locale }}
{{ this.site.timezone }}
{{ this.site.theme }}{% if this.site.code === 'english' %}
<h1>Only display for English</h1>
{% endif %}The locale attribute will return the current locale if it is specified, or return an empty value when none is specified.
<html lang="{{ this.site.locale }}">Use the hard_locale attribute to always return a locale value, which uses the default locale when none is specified.
<html lang="{{ this.site.hard_locale }}">