diff --git a/src/modules/unpackfs/main.py b/src/modules/unpackfs/main.py
index c0970ddfe..9eaa5c622 100644
--- a/src/modules/unpackfs/main.py
+++ b/src/modules/unpackfs/main.py
@@ -263,22 +263,7 @@ class UnpackOperation:
 
 def run():
     """
-    Unsquashes filesystem from given image file.
-
-    from globalstorage: rootMountPoint
-    from job.configuration: the path to where to mount the source image(s) for
-    copying an ordered list of unpack mappings for image file <-> target dir
-    relative to rootMountPoint, e.g.:
-    configuration:
-        unpack:
-            - source: "/path/to/filesystem.img"
-              sourcefs: "ext4"
-              destination: ""
-            - source: "/path/to/another/filesystem.sqfs"
-              sourcefs: "squashfs"
-              destination: ""
-
-    :return:
+    Unsquash filesystem.
     """
     PATH_PROCFS = '/proc/filesystems'
 
diff --git a/src/modules/unpackfs/unpackfs.conf b/src/modules/unpackfs/unpackfs.conf
index 755fc77c5..ce50d8f29 100644
--- a/src/modules/unpackfs/unpackfs.conf
+++ b/src/modules/unpackfs/unpackfs.conf
@@ -1,5 +1,21 @@
+# Unsquash / unpack a filesystem. Multiple sources are supported, and
+# they may be squashed or plain filesystems.
+#
+# Configuration:
+#
+#   from globalstorage: rootMountPoint
+#   from job.configuration: the path to where to mount the source image(s)
+#       for copying an ordered list of unpack mappings for image file <->
+#       target dir relative to rootMountPoint.
+
 ---
 unpack:
+# Each list item is unpacked, in order, to the target system.
+# Each list item has the following attributes:
+#   source: path relative to the live / intstalling system to the image
+#   sourcefs: ext4 or squashfs (may be others if mount supports is)
+#   destination: path relative to rootMountPoint (so in the target
+#       system) where this filesystem is unpacked.
     -   source: "_root-image_"
         sourcefs: "squashfs"
         destination: ""