Brackets are used to indicate when a style override has been applied to some text in the text-editor window.

If there are multiple, overlapping overrides, then the brackets will be shown in different colours to indicate while override is which.

• In the example above, there is one style override on the two words "world leader" (blue brackets).
• There is another, additional style override on the word "leader" (red brackets).
• And yet another style override on the letters "ad" in the word "leader" (green brackets).

NOTE:
If you have multiple non-overlapping style overrides, they will all use blue brackets. It is only when the style overrides overlap that multiple colours are used.