NerdCow

The plugin adds an additional field below the page title on the page edit screen. The value from that field acts as an internal page title that is only visible to back-end users. Thanks to this you can have a user-friendly page title for your website visitors while keeping a separate page title that is obvious to your editors and administrators.
For example, you could have a form submission thank you page with a public title that reads “We look forward to speaking with you”, but keep an internal one that says “Contact us – thank you page” without affecting what front-end users see.

Internal Page Title

Adds the internal page title for organisation use.

bitsandarts

WP attend is an easy to use plugin for the creation and managing of activities. 
People can subsribe to receive attendance emails and can confirm or deny their attendance with one click. 
You can easily create, manage and delete activities via a calendar, and choose to send attendance emails to your subscribers. 
A clear overview of attendances is consultable per activity.
<h4>Features:</h4>
<ul>
<li>Shortcode for a calendar to add, edit and delete activities</li>
<li>Shortcode for a registration form to subsribe</li>
<li>One click attendance confirmation emails for subscribers</li>
<li>Overview of attendances per activity</li>
<li>Manage your subscribers</li>
<li>Add custom privacy policy for subscribers</li>
</ul>
<blockquote>
Documentation 
 Please visit the WP attend website for the <a href="https://wp-attend.com/documentation" rel="nofollow ugc">documentation</a>
</blockquote>

WP Attend

This plugin allows easy creation of events and registration of attendances via email.

Internal Page Title vs WP Attend