Player group labels show the names of player groups as vertical text on vertical brackets to the left of staff labels. They allow you to identify groups of staves and are typically used in large-scale works, such as for orchestra and double choir.
Player group labels show full player group names by default. Short player group names are used when the full player group name is longer than the bracket.
You can show player group labels in each layout independently.
Tip
Player group labels use the Player Group Labels paragraph style, which you can edit in the Paragraph Styles dialog.