Although it is true that "llamado" is not, strictly speaking, an adjective, it is a past participle that can accompany a noun.
The question is valid in that "llamado" usually appears after the noun it modifies, for example:
- En algunos lugares de Galicia se hace un festejo llamado "entierro de la sardina". (Instead of "festejo", we could find other nouns like "acontencimiento", "celebración", etc.) Notice that "entierro de la sardina" should be between quotes, as it is the name given to a ceremony.
Since in the given sentence the noun does not appear, "llamado" (which can also appear in the feminine and in the plural) will appear before the name that is given to that tacit noun:
- En Valencia practican un juego de naipes llamado "truco" => En Valencia juegan el llamado "truco".
- La (misión) llamada "operación militar especial" es en realidad una invasión.
- Los (elementos) llamados "activos intangibles" son difíciles de valorizar.