Group layers are used to group together multiple layers so that they can be manipulated as one.
They're also very useful for organizing complex projects. You can think of a group layer as a
"folder" that can contain files (layers) and other folders (group layers). When you move a
group layer, turn it invisible, or apply an effect (such as a layer shadow), these are all
applied to every layer contained within the group layer.
There are three editing modes available for group layers:
Group,
Bone, and
Animation.