Hi glad to answer your question, basically Mazabhi is sort of like a jaat, or caste, hence like Jatts or Ramgharias.
As Sikhs, we should not label our brothers by hindu caste names, but they are Sikhs, they are not a jatha, more of just a sort of lower caste as you would say.
They have great faith in Bhagat Ravi Das Ji as well.