- * @param string $path Absolute path to search.
- * @param mixed Array of extensions to find, string of a single extension, or null for all extensions.
- * @param int $depth How deep to search for files. Optional, defaults to a flat scan (0 depth). -1 depth is infinite.
- * @param string $relative_path The basename of the absolute path. Used to control the returned path
- * for the found files, particularly when this function recurses to lower depths.
+ * @param string $path Absolute path to search.
+ * @param array|string|null $extensions Optional. Array of extensions to find, string of a single extension,
+ * or null for all extensions. Default null.
+ * @param int $depth Optional. How many levels deep to search for files. Accepts 0, 1+, or
+ * -1 (infinite depth). Default 0.
+ * @param string $relative_path Optional. The basename of the absolute path. Used to control the
+ * returned path for the found files, particularly when this function
+ * recurses to lower depths. Default empty.
+ * @return array|false Array of files, keyed by the path to the file relative to the `$path` directory prepended
+ * with `$relative_path`, with the values being absolute paths. False otherwise.