I’m struggling to get a ‘default currency symbol’ for the actual locale used. Perhaps it is wrong to assume that there is such a thing for a certain region/country?

Using the :currency format just gives the number but without a currency symbol:

Cldr.Number.to_string 1234.31, format: :currency, locale: "de"
{:ok, "1.234,31"}

Explicitly specifying the currency gives the desired result:

Cldr.Number.to_string 1345, currency: :EUR, locale: "de"
{:ok, "1.345,00 €"}

Can :EUR somehow be derived from the given locale?

My Cldr config is as follows:

defmodule Backend.Cldr do
  use Cldr,
    locales: ["de", "en"],
    default_locale: "en",
    json_library: Jason,
    gettext: Backend.Gettext,
    data_dir: "./priv/cldr",
    otp_app: :backend,
    precompile_number_formats: ["¤¤#.##0,##"],
    providers: [Cldr.Number, Cldr.Unit, Cldr.List, Cldr.Calendar, Cldr.DateTime],
    generate_docs: true
end