"I,R,C,W,E,F" are the message categories of pylint. Currently we have a very low standard and only enable the most serious classes (i.e. "E" (for error) and "F" (for fatal)) but disable the rest. With code quality being improved, we can consider enabling more message classes later on. You can get more information on this by running "pylint --long-help" and "pylint --list-msgs".

The other items in the list e.g. "design" and "newstyle" are checkers we've disabled (for similar purpose).