mlewand
commented
6 years ago It uses plugin from a third party provider m.lewandowski that we have some influence on 😄 Reason why we did so is that there's just a very small plugin, that CKSource does not need to support to. It's just for demo purpose.
It seems that sample: https://sdk.ckeditor.com/samples/balloontoolbar.html use non CKSource plugin open link. It could be nice to make this sample base on CKSource plugins exclusively. Plugins are linked as submodule in SDK repository here: https://github.com/ckeditor/ckeditor-sdk/tree/master/samples/assets/plugins