I want to know what is uloom e garibah. Where is it found? What branch of knowledge is it from and how does this work?

This is a branch of metaphysical knowledge . It was explained in some of the traditions of the Ahlul bait (as). It’s allowed for one to study it so long as it’s for sincere reason. Branches of it are jafr, harf, Nujoom etc.
The aim of it is to understand things as they are