Custom packaged CKEditor: Make buttons available on profle configuration page
I found the solution myself.

Earlier I was using "CKEditor 4 Presets Builder" available at https://github.com/ckeditor/ckeditor-presets . That is not required. I just have to put copy of descriptionlist plugin within "plugins" directory of CKEditor library. Then those three buttons started to appear in CKEditor profile configuration page.