This page has different content in the sidebar, see html_sidebars in conf.py <../conf.py>:
../conf.py
Instead of displaying the whole TOC in the sidebar with globaltoc.html, a local TOC can be shown with localtoc.html.
If you don't like the search button in the topbar, you can also put a search field into the sidebar by selecting the template searchbox.html.
Like the search button, this is only available when JavaScript is enabled.