The Matrix Awakens demo had some of the assets released to the Unreal Engine marketplace as separate packs, [1]the map, [2]buildings, crowds, and vehicles.
The matrixcity map is different, but is somewhat similar to that of the map in Matrix Awakens. You can see from the design breakdown on [3] this page by a technical lead on the Matrix Awakens project.
edit. If you look further into the [4]github codebase, under the MatrixPlugin section it explicitly states that they used the city-sample project.