UML Profile Metaclass

Metaclass is a profile class and a packageable element which may be extended through one or more stereotypes.
A metaclass may be shown with the optional stereotype «Metaclass» shown above or before its name (all lower-case «metaclass» was used in UML versions prior to 2.4).

Metaclass Component
Metaclass may be extended by one or more stereotypes using special kind of association - extension.

Stereotype Computer extends metaclass Device

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