It's probably an A-100 offshoot.
According to globalsecurity.org...
Fearing India’s defense preparedness, Pakistan is teaming up with China to test new weapons with the Fatah-1 guided multiple-launch rocket system...
According to Director General of Pakistan Army, Media Wing, Major General Babar Iftikhar, Fatah-1 weapon system can hit targets up to a range of 140 km. "The Weapon System will give Pakistan Army capability of precision target engagement deep in enemy territory," said Iftikhar. Pakistan has not shared any additional information on this rocket system...
Pakistan’s press reported that the Fatah-1 is indigenously developed and it seems likely that it is an evolutionary off shoot of the Chinese A-100 system that is in service with the Pakistan army. This rocket is produced in Pakistan and has provided the country with useful experience in producing and utilising long-range rocket artillery systems.
They previously claimed the A-100 was indigenous. It isn't.
Inter Services Public Relations, the media wing of the Pakistani military, previously claimed "A-100 Rocket has been indigenously developed by Pakistani scientists and engineers." The A-100 is a Chinese rocket system which Pakistan purchased and produce locally, but it wasn't developed by Pakistani scientists and engineers as claimed.