Translate Fancybox-Button

I am trying to change the tooltip of the fancyboy3 close button, but nothing seems to help. I tried
tpl: { closeBtn: '<a title="Test" class="fancybox-item fancybox-close" href="javascript:;"></a>'} as well as

lang : 'de',
i18n : {

    'de' : {
        CLOSE       : 'Test',

    }
}

but both versions did not help. What am I doing wrong?

$('#btn-slider-edit').fancybox({
        fullScreen: false,
        closeBtn: true,
        iframe: {
            css: {
                width: '80%',
                height: '80%'
            }
        },
        tpl: {
            closeBtn: '<a title="Test" class="fancybox-item fancybox-close" href="javascript:;"></a>'
        }
    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

If you are using fancyBox v3.1, then

1) Your first snippet works as expected:

$( '[data-fancybox]' ).fancybox({
  lang : 'de',
  i18n : {
    'de' : {
      CLOSE : 'Test',
    }
  }
});

https://codepen.io/anon/pen/bReeow

1) This is how you can change button template:

$( '[data-fancybox]' ).fancybox({
    btnTpl : {
    close  : '<button data-fancybox-close class="fancybox-button fancybox-button--close" title="{{CLOSE}} - TEST"></button>'
  }
});

https://codepen.io/anon/pen/BZzzdK