Collect & display data from current admin screens contextual hooks and from which hook on some globals are available.

current_admin_info.php

<?php
! defined( 'ABSPATH' ) AND exit;
/**
 * Plugin Name: Current admin screen info
 * Description: Show information about contextual hooks and availability of globals in the admin UI.
 * Version:     2012-09-13.0317
 * Author:      Franz Josef Kaiser <wecodemore@gmail.com>
 * Author URI:  http://unserkaiser.com
 * License:     The MIT License (MIT)
 * 
 * Copyright:   © Franz Josef Kaiser 2011-2012
 */



if ( ! class_exists( 'current_screen_data' ) )
{

/**
 * @package    Current Screen Data
 * @subpackage Abstract/Base
 */
abstract class current_screen_data
{
	protected $data = array();

	public function __construct()
	{
		// Add a subarray for each sub class with the class name as key
		if ( ! array_key_exists( get_class( $this ), $this->data ) )
			$this->data[ get_class( $this ) ] = array();

		add_action( 'all', array( $this, 'collect' ) );

		add_filter( 'contextual_help', array( $this, 'show' ), 10, 3 );
	}

	public function show( $help, $screen_id, $screen )
	{
		if ( 
			! method_exists( $screen, 'add_help_tab' )
			OR ! current_user_can( 'manage_options' )
			OR ! defined( 'WP_DEBUG' )
			OR ! WP_DEBUG
		)
			return $help;

		foreach ( $this->data as $title => $set )
		{
			$screen->add_help_tab( array(
				 'id'      => "{$title}-screen-help"
				,'title'   => ucwords( str_replace( '_', ' ', $title ) )
				,'content' => $this->markup( $set )
			) );
		}

		return $help;
	}

	// Data Collector: Must get defined in child/extending class
	abstract protected function collect();

	protected function markup( $set )
	{
		sort( $set );
		return sprintf(
			 "<ul><li>%s</li></ul>"
			,implode( "</li><li>", $set )
		);
	}
} // END Class current_screen_data

} // endif;



if ( ! class_exists( 'current_admin_hooks' ) )
{
	add_action( 'plugins_loaded', array( 'current_admin_hooks', 'init' ) );

/**
 * @package    Current Screen Data
 * @subpackage Contextual Hooks
 */
final class current_admin_hooks extends current_screen_data
{
	private static $instance;

	public static function init()
    {
		null === self :: $instance AND self :: $instance = new self;
		return self :: $instance;
	}

	public function collect()
	{
		global $hook_suffix;
		// We're done: Remove callback
		if ( 'contextual_help' === current_filter() )
			remove_filter( current_filter(), __FUNCTION__ );

		// Only add when we got context and the current filter has context
		if (
			! empty( $hook_suffix )
			AND strstr( current_filter(), $hook_suffix )
		)
			$this->data[ get_class() ][] = current_filter();
	}
} // END Class current_admin_hooks

} // endif;



if ( ! class_exists( 'current_admin_globals' ) )
{
	add_action( 'plugins_loaded', array( 'current_admin_globals', 'init' ) );

/**
 * @package    Current Screen Data
 * @subpackage Globals/Availability
 */
final class current_admin_globals extends current_screen_data
{
	private static $instance;

	public $globals = array(
		 'current_user'
		,'hook_suffix'
		,'menu'
		,'page'
		,'pagenow'
		,'parent_file'
		,'self'
		,'submenu_file'
		,'submenu'
		,'taxnow'
		,'typenow'
		,'userdata'
	);

	public static function init()
	{
		null === self :: $instance AND self :: $instance = new self;
		return self :: $instance;
	}

	public function collect()
	{
		foreach ( $this->globals as $key => $var )
		{
			// Check availability in global context
			if ( ! empty( $GLOBALS[ $var ] ) )
			{
				$global = $GLOBALS[ $var ];

				// Add to result
				$this->data[ get_class() ][] = sprintf(
					 "<td><code>$%s</code></td><td><pre>%s</pre></td><td>%s</td>"
					,$var
					,var_export($global, true)
					,current_filter()
                );

				// Don't loop this one the next time
				unset( $this->globals[ $key ] );
			}

			// We're done: Remove callback & Return
			if ( 
				empty( $this->globals )
				OR 'contextual_help' === current_filter() 
			)
				return remove_filter( current_filter(), __FUNCTION__ );
		}
	}

	protected function markup( $set )
	{
		sort( $set );
		return sprintf(
			 "<p>Filters where globals are already available.</p><table class='widefat'>%s<tr>%s</tr></table>"
			,'<thead><tr><th>Name</th><th>Data</th><th>Hook</th></tr></thead>'
			,implode( "</tr><tr>", $set )
		);
	}
} // END Class current_admin_globals

} // endif;

Now moved it to a repo. Please feel free to fork this one instead.