diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index c7482d8775..b2721628e3 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -534,6 +534,19 @@ function unzip_file($file, $to) {
 		return _unzip_file_pclzip($file, $to, $needed_dirs);
 }
 
+/**
+ * This function should not be called directly, use unzip_file instead. Attempts to unzip an archive using the ZipArchive class.
+ * Assumes that WP_Filesystem() has already been called and set up.
+ *
+ * @since 3.0
+ * @see unzip_file
+ * @access private
+ *
+ * @param string $file Full path and filename of zip archive
+ * @param string $to Full path on the filesystem to extract archive to
+ * @param array $needed_dirs A partial list of required folders needed to be created.
+ * @return mixed WP_Error on failure, True on success
+ */
 function _unzip_file_ziparchive($file, $to, $needed_dirs = array()) {
 	global $wp_filesystem;
 
@@ -579,6 +592,19 @@ function _unzip_file_ziparchive($file, $to, $needed_dirs = array()) {
 	return true;
 }
 
+/**
+ * This function should not be called directly, use unzip_file instead. Attempts to unzip an archive using the PclZip library.
+ * Assumes that WP_Filesystem() has already been called and set up.
+ *
+ * @since 3.0
+ * @see unzip_file
+ * @access private
+ *
+ * @param string $file Full path and filename of zip archive
+ * @param string $to Full path on the filesystem to extract archive to
+ * @param array $needed_dirs A partial list of required folders needed to be created.
+ * @return mixed WP_Error on failure, True on success
+ */
 function _unzip_file_pclzip($file, $to, $needed_dirs = array()) {
 	global $wp_filesystem;