[rvdmei]

This is HN at it’s best, nobody answered the original question. Diagrams such as the one on the git-lfs site are most likely created with the traditional tools in the Adobe Creative Suite (or something similar). I have seen and used my share of design, diagramming and modeling tools over pas 20-30 years and until now I haven’t run into anything that ticks all the boxes. Usually diagramming and modeling tools aren’t the ones to make something look really nice.