Regulatory markings have been relegated to the bottom cover/air inlet, where we find a few more informative tidbits:

The Mac Pro Late 2013 is identified as model A1481 with an EMC Number of 2630...

...and it's rated for 100-240 volts AC, making it a willing international travel partner.

There can only be one fan. The Mac Pro is vented by a single fan, which pulls air from under the case, through the core, and out the top of the case.