Denis Žoljom

The plugin will provide a collapsible HTML <code><details></code> block with a <code><summary></code> element that will be shown when the element is collapsed. Inside the details you can put as many paragraphs or code blocks as you want.
<h4>Requirements</h4>
<ul>
<li>PHP 5.6 or greater (recommended: PHP 7 or greater)</li>
<li>WordPress 5.0 or above (because of the Gutenberg editor)</li>
</ul>

Details Summary Block

This plugin provides a simple block for the `` HTML element.

Jonas Hjalmarsson

A single shortcode you can drop into any post, page, or text widget to get a click-to-expand “read more” toggle. The output is a native HTML <code><details></code> element styled with a small inline stylesheet — nothing else.
The point is the absence of features. There is no settings page, no animation library, no editor block panel with twelve toggles. If you need a read-more on one paragraph in one post, you do not want a plugin that wants to manage your whole site.
Usage:
<pre><code>[expand title="My title"]
The content goes here.
<img src="even-images-can-go-in-here.jpg" />
And wrap up with a closing expand tag.
[/expand]
</code></pre>
Supports a custom CSS class via <code>[expand class="my-class"]</code> and works with WordPress oEmbeds and other shortcodes nested inside.

Simple Expand – Lightweight Read more toggle

Adds an [expand] shortcode that wraps content in a native HTML `` toggle. No JavaScript, no settings page, no bloat.

Details Summary Block vs Simple Expand – Lightweight Read more toggle