Question: Where do inputs for benchmark_n_body come from?

Hi. I am learning to use Julia GPU programming for many body simulations. I am trying to understand how to use PointNeightbors for calculating neighbor lists. Looking through the tests and benchmarks it is not clear to me where the inputs come from for the line: https://github.com/trixi-framework/PointNeighbors.jl/blob/ab74c0284561b177e2df4e46d6bdef0d0168ebd2/benchmarks/n_body.jl#L15