Show callbacks using `comment_text` or `get_comment_text` filters

functions.php

// to be added in functions.php within the PHP tags

function spc_list_comment_filters() {
	// exit if not on a page that show comments (the Comments page or Edit post/page screen)
	global $pagenow;
	if ( 'edit-comments.php' != $pagenow && 'post.php' != $pagenow ) {
		return;
	}

	// get global variable containing list of registered filters
	global $wp_filter;

	// build string to be output
	$output = '<div style="margin-left:160px; padding-bottom:60px; padding-left:20px;">';
	$output .= '<h1>Show Parent Comment Debug Info</h1>';

	// loop through each filter and output comment_text and get_comment_text
	foreach ( $wp_filter as $key => $val ) {
		if ( $key == 'comment_text' || $key == 'get_comment_text' ) {

			$output .= "<h2>$key</h2><ul>";

			// loop through each callback that access these filters and list their details
			$callbacks = $val->callbacks;
			foreach ( $callbacks as $key2 => $value2 ) {
				$output .= "<li>add_action( '$key', '" . key($value2) . "', '" . $key2 . "', '" . $value2[key($value2)]['accepted_args'] . "');";

				// let try to get the file where the function lives. Note only for functions, not classes (4.7 had changes so my old code won't work for classes)
				try {
						$ref = new ReflectionFunction( key($value2) );
						$output .= " &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Function defined in: " . $ref->getFileName();
				}
				catch ( Exception $e ) {
						$output .= " &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Function defined in: File name not available";
				}

				$output .= "</li>";
			}

			$output .= '</ul>';
		}
	}

	// close the div and output the string
	$output .= '</div>';
	echo $output;
}
add_action( 'admin_footer', 'spc_list_comment_filters' );