It's a very common term in reverse engineering, and low level programming in general. In VMs you usually say "stolen" to refer to bytes/instructions/constants that have been taken from the original binary and put somewhere else (whether obfuscated or not, whether still in the local binary or in a server like with denuvo)

The “stolen” constants/instructions are bits of code that were in the original (VM-obfuscated) binary. These constants/instructions are deleted from the binary and provided by the server in an obfuscated form. Effectively, the binary you get when buying the game is incomplete: you get a dynamic, encrypted, system-dependent patch from the server that supplies the missing pieces (the “stolen” pieces).