WordPress at a glance
function is not described

wp_cache_append_tag() WPSCache 1.0

No Hooks.

Return

Null. Nothing.

Usage

wp_cache_append_tag( $buffer );

Code of wp_cache_append_tag() WPSCache 1.7.1

<?php
function wp_cache_append_tag( &$buffer ) {
	global $wp_cache_gmt_offset, $wp_super_cache_comments;
	global $cache_enabled, $super_cache_enabled;

	if ( false == isset( $wp_super_cache_comments ) )
		$wp_super_cache_comments = 1;

	if ( $wp_super_cache_comments == 0 )
		return false;

	$timestamp = gmdate('Y-m-d H:i:s', (time() + ( $wp_cache_gmt_offset * 3600)));
	if ( $cache_enabled || $super_cache_enabled ) {
		$msg = "Cached page generated by WP-Super-Cache on $timestamp";
	} else {
		$msg = "Live page served on $timestamp";
	}

	if ( strpos( $buffer, '<html' ) === false ) {
		wp_cache_debug( site_url( $_SERVER[ 'REQUEST_URI' ] ) . " - " . $msg );
		return false;
	}

	$buffer .= "\n<!-- $msg -->\n";
}