Why Are There Holes On The International Space Station?

Obviously, these holes were not made by space rats but humans. But what's inside them?

They are elements and computing pieces "being evaluated for the effects of atomic oxygen, ultraviolet, direct sunlight, radiation, and the extremes of heat and cold" outside the International Space Station. Scientists want to test their endurance against the harshness of space.

I want to lick these things. I know I would probably burn or freeze my tongue by doing it, but some of these things look like lollies. Mmmm, lollies. [NASA]