You are on the development sites of the plausj subproject bank_german. This project aims to provide a high quality check digit calculation library for german bank accounts.
Currently there are about 130+ different strategies which are used by german banks. On releases this library will have them all. ;-)
The "Deutsche Bundesbank", central bank of germany, provides documation and mapping data how to calculate the check digits and how to map the strategies to the bank codes.
This subproject is in BETA-state now. That means that it is functional complete but lacks some testing. Further the code smells a bit and we need to do some refactoring.
This is the roadmap to the first release. We do not provide a timeframe at the moment but work as fast as possible.