devdocs/assets/javascripts/templates/notice_tmpl.js

const notice = (text) => `<p class="_notice-text">${text}</p>`;

app.templates.singleDocNotice = (doc) =>
  notice(` You're browsing the ${doc.fullName} documentation. To browse all docs, go to
<a href="//${app.config.production_host}" target="_top">${app.config.production_host}</a> (or press <code>esc</code>). `);

app.templates.disabledDocNotice = () =>
  notice(` <strong>This documentation is disabled.</strong>
To enable it, go to <a href="/settings" class="_notice-link">Preferences</a>. `);