This domain is found in monooxygenases involved in the biosynthesis of several antibiotics by Streptomyces species. It's occurrence as a repeat in Streptomyces coelicolor SCO1909 is suggestive that the other proteins function as multimers. There is also a conserved histidine which is likely to be an active site residue.
Jiyao W et al.(2023). "The conserved domain database in 2023.",