Just for balance, Pylance is proprietary but the core of it is the Pyright library which is completely open (see: https://github.com/microsoft/pyright https://g

Just for balance, Pylance is proprietary but the core of it is the Pyright library which is completely open (see: https://github.com/microsoft/pyright https://github.com/microsoft/pyright). It would be nice if they were more transparent about the differences between the two and why Pylance is closed. There are a few github issues where Microsoft PMs basically stonewall the community with very little info.