What does it mean to be a fully human monoclonal antibody?
I found this small article that seems to cover all your questions:

https://www.sciencedirect.com/topics/medicine-and-dentistry/human-monoclonal-antibody

Summary:

Being considered a human monoclonal (many of the identical antibody, as opposed to different antibodies for the same target) antibody does not mean it is produced by a human body; it means that the fc-region of the antibody is human-like, which aims at avoiding immune reactions against that antibody if injected into humans.
So the human antibody can originate from animals (e.g. rats or rabbits) with humanized antibody genes or from immortalized human cell-lines (lymphocytes).