It’s not really serious, but caused me some trouble when trying to create tax rules. I cannot delete any of the, TRY says all of them are part of the basic configuration.
In spite of that - is there a chance to get rid of the surplus ones?
Thank you. You led me to the solution - I had two account tables at a time - SKR03 and SKR04, using only SKR04. So deactivating the SKR03 module (module page -> propeller menu) erased the surplus tax groups.