The donation field in kde.org footer and the one-time donation field in kde.org/donate does not have localised formatting for the decimal field and the currency sign.

Something like:

function formatCurrency(value, locale = navigator.language, currency = 'EUR') {
            const formatter = new Intl.NumberFormat(locale, {
            style: 'currency',
        currency: currency
    });
    return formatter.format(value);
}

would make it look more professional, instead of an out-of-field currency sign.