BankPython

Very interesting overview of how PythonLanguage systems look in BigFinance

https://calpaterson.com/bank-python.html

Doesn't entirely surprise me.

The pattern of everything around a single database

Which is not relational but primitive table based

Some ideas look familiar to me from when I used CacheObjectScript in enterprise software. In Intersystems' version of MUMPS even source code is in the db

Some I can kind of infer from ClojureLanguage (built for Datomic, used in banks)