I wonder if it’s bovine hyaluronidase. If it human recombinant, halo could go after them for patent infringement. Below is the link for the study. It does not specify “human” whereas almost all enhanze studies specify human recombinant hyaluronidase. Non-human hyaluronidase has been around going back several decades but it fell out of favor due high rate of immune reaction.
I seem to remember there was speculation that Merck was working with a Korean company. I don't think it was BMI Korea, but BMI uses recombinant ovine hyaluronidase.
"But other substances can also be used. Comera Life Sciences recently published a study demonstrating the use of caffeine to stabilise the subcutaneous antibody formulation of Bristol Myers Squibb’s Yervoy (ipilimumab)."