"The module, which was originally constructed as a backup for the core ISS Zarya FGB module back in the 1990s""speculation that the MLM could be repurposed once more, to serve as an independent Russian space station"
So this module was originally constructed (by the Soviet Union as was), as a backup for Zarya, which was originally intended to be part of Mir 2*, and now having sat in a warehouse somewhere for thirty years, might still end up being part of an independent Russian station. Funny how things go around eh?
* The main Russian module in the ISS, Zvezda, is actually an evolution of the original Salyut space station module, and was originally intended to for the core of Mir 2, up until the US realised that they couldn't afford Space Station Freedom**, and the Russians realised that without the Soviet Union around, they couldn't pay for Mir 2 either, so both countries got together and built an International Space Station.
** Never allow Americans to name things, they're crap at it.
Biting the hand that feeds IT
