It's some kind of security screw, we use similar ones at work but I think they have 5 prongs.
A pair of cutters should grip the head and unscrew them then replace with Allen headed bolts as you are bound to damage them.
Pete
Indeed , obscure ( for this country) tamper resistant. Looks like the orange handled item is the required tool-Is that a Japanese male line head screw? I can't quite see the picture