The localisation in ku-arab is done for the Sorani language. Sorani (iso 639-3 ckb) is written primarily in the Arabic script. The Kurmanji language (kmr) is effectively what is left in the ku.wikipedia. The naming of this project is unfortunate because there are two more languages that make part of this macro language. This can however not be helped.
The Kurmanji language is written both in Arabic and Latin and therefore the conversion from Latin to Arabic is still valid. When the ku-arab localisation data has been moved, there is no ku-arab localisation left. This may fall back to ckb.
The Sorani language is called کوردی in Sorani (actually Kurdi.. they do not call it Sorani themselves).
Sorani is eligible for a new project as per the language committee.