Arcanist already integrates nicely with Pylint. However, Python 3 is increasingly recommended and used over Python 2. Pylint is only designed for Python 2. Pylint3 is used for Python 3, and is likely going to be needed by any development team using Python 3 (ours included).

I know I can add this linter in manually, which I'll look into as a short-term solution. However, because Pylint3 is going to be in increasingly high demand, it should probably be added to Arcanist's linters. Integration should be trivial, since it appears to be functionally identical to Pylint.