There are no links to sources on their site, and they don't provide datasheets. To request sources under GPL you need to get binaries first. I live in Russia, and I've never seen Elbrus in real use anywhere. It's not marketed or sold to general public. I think target market is government's security agencies. Of course they get sources anyway for audit and have no incentive to publish them.
[1] (russian) http://www.mcst.ru/os_elbrus