How authentic is the book "Al-Ifṣāḥ ‘an Ma‘ānī al-Ṣiḥāḥ"?

Ibn Hubayra explained Sahih al-Bukhari and Sahih Muslim in his book Al-Ifsah an Ma'ani as-Sihah, relying on Al-Humaydi's Al-Jam' bayna as-Sahihayn. The book Al-Ifsah is reliable and highly regarded, praised by imams and memorizers of hadith. Its importance lies in being the first explanation of both Sahihayn together. Al-Hafiz Ibn Rajab mentioned that in this book, after the hadith "Whomever Allah desires good for, He grants him understanding in religion," Ibn Hubayra explained the meaning of fiqh and discussed issues of fiqh upon which the four imams agreed and disagreed. Ibn Hubayra stated in the introduction to Al-Ifsah that he intended to compile the authentic hadiths of the Messenger of Allah along with their jurisprudence, especially those within which the schools of thought have become established. After reviewing Ibn Abd al-Barr's At-Tamhid and observing its limitation to the hadiths of Al-Muwatta, he decided to rely on the two Sahihs, whose hadiths the Ummah has accepted, and made them the basis for his book, depending on Al-Humaydi's book Al-Jam' bayna as-Sahihayn.