Can anybody please tell me what type of bolt is this? I can not find any tool to remove it.
Those are used in vehicles to reduce theft of the attached item.
In the case of the photograph, it is holding in a sound system, perhaps the most commonly stolen item in a vehicle.
I have only seen them in non-automotive applications where someone is using them outdoors to prevent theft.
When I enlarged the picture as big as it would go,(click on the picture, there will be a plus sign with a magnifying glass, then click on it again to get it larger still) I could not see any definition of a bolt head setting on a metal plate to hold something. It looks like a stamp that shaped the metal plate also stamped the presumed bolt head too. If that was truly a bolt, the lines where the bolt would meet the plate would be clearly defined and I would figure the metal color would at least be slightly different from the bolt to the plate.
I would have no idea why it would be made that way, but it appears to be part of the plate/bracket.