Archetypes with the multiclass trait represent diversifying your training into another class’s specialties. Feats and Talents with this trait enable taking parts of other classes and applying it onto another character without much other investment.
Multiclassing falls under this umbrella, as it was the classic term for such.
Class Archetype Templates that have the 'Cross-Classing' trait
Subclasses that have the 'Cross-Classing' trait
Dedication Templates that have the 'Cross-Classing' trait
Heritages that have the 'Cross-Classing' trait
Primary Feats that have the 'Cross-Classing' trait
Secondary Feats that have the 'Cross-Classing' trait
Talents that have the 'Cross-Classing' trait
Other things have the 'Cross-Classing' trait
