Cldr.Rbnf.for_locale

You're seeing just the function for_locale, go back to Cldr.Rbnf module for more information.

for_locale(language_tag)

for_locale(Cldr.LanguageTag.t()) ::
  {:ok, map()} | {:error, {module(), String.t()}}

Returns {:ok, rbnf_rules} for a locale or {:error, {Cldr.NoRbnf, info}}

for_locale(Cldr.Locale.locale_name() | Cldr.LanguageTag.t(), Cldr.backend()) ::
  {:ok, map()} | {:error, {module(), String.t()}}

Returns {:ok, rbnf_rules} for a locale or {:error, {Cldr.NoRbnf, info}}

locale is any locale name returned by Cldr.Rbnf.known_locale_names/1
backend is any module that includes use Cldr and therefore is a Cldr backend module