Verification Language Vlang.
This package has the base simulator and the data modules, which include the constrained randomization unit. UVM package is available separately because it comes with a different opensource license.
Vlang is a domain specific embedded language. And since the language is built on top of the D programming language, you need a latest release of the DMD compiler to compile Vlang source files.
Vlang works with 2.064 or a later release of DMD compiler. DMD compiler can be downloaded from the page http://dlang.org/download.html. At this point Vlang has been tested on only 64-bit Linux machines.