It is a stiffener plate between block and tranny and goes on the front just above the exhaust pipe. Paired holes go to tranny, single hole goes to block with either a bolt (US) or stud and nut (Japan). A stay to the exhaust manifold pipe connection point is also mounted on the bolt/stud and mounts on top of the plate.
I pretty sure I learned this from the service manual. I'll try to find the page number when I get a chance. EDIT: Page EM-67, EM-68 here:
http://www.camrystuff.com/manuals/Ge...hanical_I4.pdf
The stiffener plate on the backside under the intake manifold looks very similar but is different. It also has paired holes on one end a single hole on the other, but the paired holes go on the block and the single one to the trans.