diff --git a/cura/Machines/QualityGroup.py b/cura/Machines/QualityGroup.py
index 1ea7ef6903..b9f2451ddc 100644
--- a/cura/Machines/QualityGroup.py
+++ b/cura/Machines/QualityGroup.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2018 Ultimaker B.V.
+# Copyright (c) 2019 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
 from typing import Dict, Optional, List, Set
@@ -11,19 +11,22 @@ from UM.Util import parseBool
 from cura.Machines.ContainerNode import ContainerNode
 
 
+##  A QualityGroup represents a group of quality containers that must be applied
+#   to each ContainerStack when it's used.
 #
-# A QualityGroup represents a group of containers that must be applied to each ContainerStack when it's used.
-# Some concrete examples are Quality and QualityChanges: when we select quality type "normal", this quality type
-# must be applied to all stacks in a machine, although each stack can have different containers. Use an Ultimaker 3
-# as an example, suppose we choose quality type "normal", the actual InstanceContainers on each stack may look
-# as below:
-#                       GlobalStack         ExtruderStack 1         ExtruderStack 2
-# quality container:    um3_global_normal   um3_aa04_pla_normal     um3_aa04_abs_normal
-#
-# This QualityGroup is mainly used in quality and quality_changes to group the containers that can be applied to
-# a machine, so when a quality/custom quality is selected, the container can be directly applied to each stack instead
-# of looking them up again.
+#   A concrete example: When there are two extruders and the user selects the
+#   quality type "normal", this quality type must be applied to all stacks in a
+#   machine, although each stack can have different containers. So one global
+#   profile gets put on the global stack and one extruder profile gets put on
+#   each extruder stack. This quality group then contains the following
+#   profiles (for instance):
+#                      GlobalStack       ExtruderStack 1     ExtruderStack 2
+#   quality container: um3_global_normal um3_aa04_pla_normal um3_aa04_abs_normal
 #
+#   The purpose of these quality groups is to group the containers that can be
+#   applied to a configuration, so that when a quality level is selected, the
+#   container can directly be applied to each stack instead of looking them up
+#   again.
 class QualityGroup(QObject):
 
     def __init__(self, name: str, quality_type: str, parent: Optional["QObject"] = None) -> None: