A full listing of the CKEDITOR.config configuration settings that you can change in order to customize the editor to your needs can be found in the CKEditor JavaScript API. Use the methods described in the Setting Configuration article from the Developer's Guide.
How Do I Find the CKEditor Configuration Settings to Change?
This website contains links to software which is either no longer maintained or will be supported only until the end of 2019 (CKFinder 2). For the latest documentation about current CKSource projects, including software like CKEditor 4/CKEditor 5, CKFinder 3, Cloud Services, Letters, Accessibility Checker, please visit the new documentation website.
If you look for an information about very old versions of CKEditor, FCKeditor and CKFinder check also the CKEditor forum, which was closed in 2015. If not, please head to StackOverflow for support.