An optional plugin for Expressive Code, an engine for presenting source code on the web.
It allows code sections to be marked as collapsed. The lines in collapsed sections will be hidden by default, replaced by a "X collapsed lines" line. When clicked, the collapsed section will be expanded, showing the previously hidden lines.
Read this plugin's documentation on the Expressive Code website to learn more about its features.
See the installation instructions for this plugin to learn how to install it on your site.