HB provides various of syntax highlighting modules, this article lists the supported styles.

The code block panel provides abilities to expand code, copy code, wrap code and toggle code line numbers.
This article shows how to install, uninstall and upgrade modules.
AKA return to top, a button to back to top.
A progress bar will be shown when opening a new page in the current tab and window.

Mermaid is a JavaScript-based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams.