x-browser-copyright seems like an attempt at something similar to the Gameboy's nintendo-logo DRM (wherein cartridges are required to have the nintendo logo bitmap before they can boot, so any unlicensed carts would be trademark infringement)
Apple famously does this with this word soup in their SMC chips, and proceeded to bankrupt a company that sold Hackintoshes and shipped it in their EFI: https://en.wikipedia.org/wiki/Psystar_Corporation
Our hard work
by these words guarded
please don't steal
(c) Apple Computer Inc
http://en.wikipedia.org/wiki/Sega_Enterprises_Ltd._v._Accola... is the legal precedent that says trying to do that won't work, but then again maybe Google thinks it's invincible and can do whatever it wants after it ironically defeated Oracle in a case about interoperability and copyright.