Some configuration options cover a group of languages, such as "English variants" (Z33034), not one language. Today the community writes the languages of an option in three forms: one language, a list of languages in the option, or a reference to a shared list. The user can register a Function for one language or for a group, and the action writes the configuration in the same form that the community uses now.

Acceptance criteria

• A user can register a Function for one language, or for an existing shared list of languages such as Z33034.
• The configuration after registration uses the same forms that the community uses now, and the selector (Z14310) reads it correctly.