Each technology is tested against a certain rule compliance set. These rules help to keep the code clean and understandable for other developers familiar with the technology in question. Violations don't mean that the code will not work, but rather that the developer is not familiar with certain ethics of writing the code. The reason why it’s so important for developers to know these sets of compliance rules is to be able to work on code in teams or easily pass the code to other developers. If the code is written poorly it will be a lot harder to understand. Our system scores the code of the candidates against these rules to see not only if the candidate improved the written code but also if they haven’t made it worse. This is why you can find that a candidate is getting points even if (s)he made no improvements in that matter; we give some points at the start, so we can reduce the score if they create additional violations compared to the code they were provided with.
If some violations have been changed, you can check what kind of violations were affected on the violations tab in the programming task section.