diff --git a/frontend/ui/downloadmgr.lua b/frontend/ui/downloadmgr.lua
index 685053299..1a6c8945a 100644
--- a/frontend/ui/downloadmgr.lua
+++ b/frontend/ui/downloadmgr.lua
@@ -1,3 +1,22 @@
+--[[--
+This module displays a PathChooser widget to choose a download directory.
+
+It can be used as a callback on a button or menu item.
+
+Example:
+    callback = function()
+        require("ui/downloadmgr"):new{
+            title = _("Choose download directory"),
+            onConfirm = function(path)
+                logger.dbg("set download directory to", path)
+                G_reader_settings:saveSetting("download_dir", path)
+                UIManager:nextTick(function()
+                    -- reinitialize dialog
+                end)
+            end,
+    }:chooseDir()
+]]
+
 local PathChooser = require("ui/widget/pathchooser")
 local UIManager = require("ui/uimanager")
 local Screen = require("device").screen
@@ -16,6 +35,8 @@ function DownloadMgr:new(from_o)
     return o
 end
 
+--- Displays a PathChooser widget for picking a (download) directory.
+-- @treturn string path chosen by the user
 function DownloadMgr:chooseDir()
     local lastdir = G_reader_settings:readSetting("lastdir")
     local download_dir = G_reader_settings:readSetting("download_dir")