From v5.6.0, Group designators may be used to assign a value to the attributes of several notes at once. For example, the $Rule:
$Color(children)="red"
turns all the current note's children to red.
Designators may also be lists of notes, either explicit literal string list
$Color(/config/one;/config/two)="red"
or implicitly computed via a find():
$Color(find($Price>5))="red"
$Color(find($Color="red"))="red"
or implicitly computed by an expression enclosed in quotation marks
$Color("collect_if(all,$Price>5,$Path)")="red"
$Color("collect_if(all,Color='red',$Path)")="blue"