Yes, most likely they use it for implementation inheritance which is sloppy anyway since it usually violates the Liskov substitution principle and also most OOP languages that have that concept tend to have issues around co- and contra-variance in either function parameter and return types or containers or both.
Yes, most likely they use it for implementation inheritance which is sloppy anyway since it usually violates the Liskov substitution principle and also most OOP languages that have that concept tend to have issues around co- and contra-variance in either function parameter and return types or containers or both.