Some of the new listers like GNU and CRAN do not follow the conventional way of making an HTTP request, hence they do not need some of the methods which are usually needed by in conventional HTTP request.

But those methods are marked abstractmethod in the core making them necessary to be present. So it is in best to remove abstractmethod to increase the readability of those listers.

@ardumount stated in D1482 to remove those decorators from the base class as they makes code immediately harder to read and will make it harder to maintain later.