What is the truth about the Book of Al-Jafr attributed to our master Ali, may Allah be pleased with him?

The book (Al-Jafr) is among the delusions and fabrications of the esoteric (Batiniyyah) sects who attribute it to Ali ibn Abi Talib or Ja'far Al-Sadiq. They claim that secrets and truths are written on the skin of "Al-Jafr" (a kid goat). This is a lie and a fabrication. Ali ibn Abi Talib denied the existence of any special revelation they possessed other than the Qur'an and what was in a scroll he had, which included rulings such as: the blood money for killing a human (Al-Aql), the ransom of a captive, and the prohibition of killing a Muslim for (killing) an unbeliever. Scholars have used this Hadith (definition) as proof that everything mentioned about Ali and the People of the House (Ahl al-Bayt) being exclusively endowed with a special knowledge given to them by the Prophet—such as Al-Jafr, Al-Bitaqa (the card/document), and Al-Jadwal (the table/schedule)—is a lie against them. Furthermore, the esoteric Qaramita fabricated lies against Ja'far Al-Sadiq, Ali, and other imams of the People of the House.