nezhar

A WordPress plugin that displays a notification if you are working on a dev environment
You can configure the message that the notice displays, and the notice CSS class. The plugin comes with 3 notice levels:
<ul>
<li>wp-dev-notice-info</li>
<li>wp-dev-notice-warning</li>
<li>wp-dev-notice-danger</li>
</ul>

WP Dev Notice

A WordPress plugin that displays a notification if you are working in a development environment

Mario Peshev

DevriX

Stanko Metodiev

Sven Hofmann

Display a notice when working on a localhost site on staging environment, based on your settings and adjustments
Activate the plugin and see a yellow notice bar indicating that you’re working on localhost.
Super helpful whenever you’re cloning a production website with virtual hosts using the same domain name, and are not sure which site are you editing. Visible both in the admin area, and the frontend to all site visitors.

DX localhost

Display a yellow notice box when you're working on localhost

WP Dev Notice vs DX localhost