Last commit to integrate libraries module broke paths for individuals not using that contrib module.

#2972670: Fixed compatibility with libraries module → changed the path to the link library from /libraries/ckeditor/plugins/link/plugin.js to:

define("ANCHOR_LINK_LIBRARY_PATH", '/libraries/link/plugin.js');

and

return 'libraries/link';

'link' is a pretty general term for in the libraries directory and could have conflicts.

I would suggest testing how this works when the libraries contrib module is NOT installed. If it needs to be a requirement, it should be added.