Cldr.Number.Symbol.all_decimal_symbols_class

You're seeing just the function all_decimal_symbols_class, go back to Cldr.Number.Symbol module for more information.

all_decimal_symbols_class(backend)

Returns a list of all decimal symbols defined by the locales configured in the given backend as a string.

This string can be used as a character class when builing a regular expression.

backend is any module that includes use Cldr and therefore is a Cldr backend module