UML Profile Reference

Reference is import relationship represented by “metaclassReference” element import and “metamodelReference” package import.
The “metaclassReference” element imports and “metamodelReference” package imports serve two purposes: (1) they identify the reference metamodel elements that are imported by the profile and (2) they specify the profile’s filtering rules.
The filtering rules determine which elements of the metamodel are visible when the profile is applied and which ones are hidden.
Note that applying a profile does not change the underlying model in any way; it merely defines a view of the underlying model. In general, only model elements that are instances of imported reference metaclasses will be visible when the profile is applied. All other metaclasses will be hidden. By default, model elements whose metaclasses are public and owned by the reference metamodel are visible.
Profile Reference - 图1image.png
Metaclass Component is referenced (imported) by profile Servlets

https://www.uml-diagrams.org/profile-reference.html