It also mentions Sibas, which is the “Siemens Bahn Automatisierungs System” (Siemens Train Automation System).

So this is probably spot on.

I suspect this is a third-party supplier who is trying to keep old Siemens driver interface systems limping along. Bold, as when we tried that it was nearly impossible to do so - the OEM had too much of a stranglehold over the design.