diff -r 2_5_1/wp-admin/includes/update.php test/wp-admin/includes/update.php
113a114,118
> 	// testing purposes
> 	// Assumes that server response will be changed to include a new element: an array "other_plugins" containing elements of $plugin_file=>'unknown' or $plugin_filename=>'current' for all the plugins for which it doesn't show updates.
> 	$response['other_plugins'] =  array('kill_messages.php'=>'unknown','kill_one_message.php'=>'unknown');
> 	error_log( print_r($response,true) );
> 
140a146,162
> function wp_plugin_update_unknown( $file ) {
> 	$output = false;
> 	$output = apply_filters('plugin_updates_unknown', $output, $file );
> 	// Note:	if filter returns false, function shows default message
> 	//			if filter returns empty string ('') function shows nothing
> 	if( $output === false ) {
> 		$current = get_option( 'update_plugins' );
> 		$output = '';
> 		if (	( isset( $current->response['other_plugins'][ $file ] ) &&
> 				$current->response['other_plugins'][ $file ] == 'unknown' ) ) {
> 			$output = __('Not Checked for Updates');
> 			$output = "<br /><span class=\"updatenotice\">{$output}</span>";
> 		}
> 	}
> 	return $output;
> }
> 
diff -r 2_5_1/wp-admin/plugins.php test/wp-admin/plugins.php
146c146
< 		<td class='vers'>{$plugin_data['Version']}</td>
---
> 		<td class='vers'>{$plugin_data['Version']}" . wp_plugin_update_unknown($plugin_file) . "</td>
diff -r 2_5_1/wp-admin/wp-admin.css test/wp-admin/wp-admin.css
4a5,15
> #plugins span.updatenotice {
> 	display: block;
> 	margin-top: .5em;
> 	font-style: italic;
> 	font-size: 85%;
> }
> 
> #plugins .vers {
> 	width: 7em;
> }
> 
Only in test/wp-content/plugins: kill_messages.php
Only in test/wp-content/plugins: kill_one_message.php