If I'm reading the contract correctly[1], the source won't be available until 2020. There's also some limitations put on the licensing that are IMO stretching (or maybe abusing) the definition of open source.
They reserve the right to make it open source in that contract, but they may or may not do so.
LA County has the right, and elsewhere they've said that they will (although of course plans change, with some caveats about device firmware and using it for your own elections
As far as I know, it’s not actually open source, but they may or may not make it open source at some point in the future. It has been frustrating because the media has been portraying it to be open source when there has never been such a commitment.