Earlier quoted context omitted.
> a large financial application Those could mean anything. Some people think 5k likes is large. Others think 100k is small. Oh well, at least they didn't say "complex".
Also, they didn't say how accurate or secure it is.
Since its proprietary, it runs in a private cloud environment and is processing only data of one "user per instance"; there is not public interface, only a VPN you have to dial in etc., so no frontend/frontpage facing the public.
Though, there are some design flaws from this perspective, because of convenience: E.g. it lets you persist the account number in the DB, if wanted.