"In addition to supporting portable, consumer, industrial, communications and medical applications with commercial and industrial temperature devices, Actel also offers ProASIC3 FPGAs with specialized screening for automotive and military systems."
"Specialized screening for automotive and military systems" means that they have done more extensive tests on otherwise identical chips.
As an example: for military chips they will certainly do every (non-destructive) test they know on every single device, say at elevated temperature with a little less than the minimum specified operating voltage... The test-devices themselves might cost $1M and be occuplied for oen hour per chip, hence they will charge you more for the final chip.
"In addition to supporting portable, consumer, industrial, communications and medical applications with commercial and industrial temperature devices, Actel also offers ProASIC3 FPGAs with specialized screening for automotive and military systems."
http://www.actel.com/products/pa3/
There seems to be a special variant of the chip for military use, hopefully without this 'debugging feature'.