frame?

boolean

(Optional) Whether the language frame is shown.

group_class?

string

(Optional) Language-group CSS class.

key?

string

(Optional) Key override for the language group.

mode?

string

(Optional) Expansion mode (e.g. append).

name?

string

(Optional) Name override for the language group.

only?

string[] | LangOverrideMap

(Optional) Two shapes (SPEC §3 C): a language allowlist ['ko', 'en'] (string[]) OR a per-language override map { ja: { validate: … } } (LangOverrideMap). The allowlist restricts the rendered languages; the override map redefines role slots per language.

title?

LocalizedText

(Optional) Language-group title.