There are 2 repositories under berlin-group topic.
Provides RESTful API, tools, adapters, and connectors for transparent access to open banking API's (for banks that support PSD2 and XS2A as well as HBCI/FinTS)
Open Source PSD2-compatible banking system emulator solution from adorsys
OpenBankingProject.ch Community APIs
Open Source implementation of XS2A connector