horike

Displays Super Global valiables for the current request.Like $_POST, $_GET, and $_COOKIE. Requires the debug bar plugin.

Debug Bar Super Globals

Hasn't received any updates in 8 years and it STILL WORKS!

Still Works (as of WordPress 5.5)

Displays Super Global valiables for the current request.Like $_POST, $_GET, and $_COOKIE. Requires the debug bar plugin.

Juliette Reinders Folmer

Subharanjan

This plugin adds two more tabs in the Debug Bar to display hooks(Actions and Filters) attached to the current request. Actions tab displays the actions hooked to current request. Filters tab displays the filter tags along with the functions attached to it with respective priority.
<h4>Important</h4>
This plugin requires the <a href="https://wordpress.org/plugins/debug-bar/" rel="ugc">Debug Bar</a> plugin to be installed and activated.
Also note that this plugin should be used solely for debugging and/or in a development environment and is not intended for use on a production site.
If you like this plugin, please <a href="https://wordpress.org/support/view/plugin-reviews/debug-bar-actions-and-filters-addon" rel="ugc">rate and/or review</a> it. If you have ideas on how to make the plugin even better or if you have found any bugs, please report these in the <a href="https://wordpress.org/support/plugin/debug-bar-actions-and-filters-addon" rel="ugc">Support Forum</a> or in the <a href="https://github.com/subharanjanm/debug-bar-actions-and-filters-addon/issues" rel="nofollow ugc">GitHub repository</a>.

Debug Bar Actions and Filters Addon

Awesome

Displays all the hooks( Actions and Filters ) for the current request in Debug Bar panel.

Debug Bar Super Globals vs Debug Bar Actions and Filters Addon