Bill Erickson

Warning This plugin is no longer supported, and does not always work with the Gutenberg block editor.
I recommend using <a href="https://wordpress.org/plugins/change-last-modified-date/" rel="ugc">Change Last Modified Date</a> instead.
<h4>Summary</h4>
Prevent the modified date from changing when making minor changes to your content.
This plugin adds a checkbox to the Publish box, “Don’t update the modified date”. When checked, saving your post does not update the post modified date.
Minor changes like adding tags or fixing typos won’t bump the modified date.
This plugin will maintain the previous modified date. It does not let you specify a custom modified date.
When you’re ready to publish a major content change, you can uncheck this setting before saving the post.
<h4>Customization</h4>
Your theme will need to use <code>get_the_modified_date()</code> to display the modified date.
This plugin only applies to the <code>post</code> post type by default. You can customize which post types it appears on using the <code>limit_modified_date_post_types</code> filter.
<pre><code>add_filter( 'limit_modified_date_post_types', function( $post_types ) {
 $post_types[] = 'page';
 return $post_types;
});
</code></pre>

Limit Modified Date

Prevent the "modified date" from changing when making minor changes to your content.

Marcin Pietrzak

Reading Position Indicator adds a stylish horizontal progress bar alongside your content, showing readers how far they’ve scrolled. It enhances user engagement by providing a clear visual cue of reading progress, ideal for blogs, articles, and long-form content.
Features 
* Horizontal progress bar displayed on posts and pages. 
* Customizable colors, opacity, rounded edges, and gradients. 
* Lightweight and performance optimized. 
* Easy setup with no coding required. 
* Translation ready. 
* Compatible with most WordPress themes.
Thank you <a href="http://pankajparashar.com/" rel="nofollow ugc">Pankaj Parashar</a> for your article on CSS-TRICKS about <a href="https://css-tricks.com/reading-position-indicator/" rel="nofollow ugc">Reading Position Indicator</a>

Reading Position Indicator

Add reading position indicator on page top.

Limit Modified Date vs Reading Position Indicator