It is literally translated as ”black-box operation(s)”.
It refers to actions within an organization which are not transparent to the general public or the “masses” within the organization, which consequently result in bad things happening. It is a metaphor of the black box, where one knows the input and the output, but doesn’t know the underlying process/transformation that occurred to change the input into the output.
Is there an idiom in English that encapsulates the same idea?