I don't think they are using the session extension, as this project provides its own binary encoding, which wouldn't be needed if the session extension is used.

I don't think they are using the session extension, as this project provides its own binary encoding, which wouldn't be needed if the session extension is used. It wouldn't affect random/date either, as the session extension doesn't replay transactions, but captures applied changes as changesets (so it would capture the results of random/date), which can then be applied to other nodes.