All of it
We sell this shirt in the NAP bookstore, where I am working for half of today (making three times what I used to make for working in a bookstore, so I can't really complain). The bookstore manager told me that people ask what it is all the time, so I wrote it down and brought it home to Dan, who confirmed that it was F=ma written in the most obscure way possible. (The marketing people didn't seem to get why that was funny... but then, that's what they need me for.) A guy came in today and was delighted that I could tell him what it was and could recognize some of the symbols, but he too wasn't sure exactly what formulation of F=ma he was looking at (he said the acceleration of the Earth was in there somewhere).
Eventually, since this is the National Academies, a prominent physicist will undoubtedly come in and recognize it at a glance. Meanwhile, though, Dan explained volume integrals and R-double-dot, but we're otherwise stumped. Can anyone help unpack the equation?