That was the original idea, but it immediately got diluted. It isn’t a good idea to hide nuances like that behind such a common word. The documentation is simply inaccurate at this point. Everything tagged permit=* is likely a permit that takes more than asking nicely to obtain, not to mention permit in the context of the street parking scheme. Even the photo that accompanies the article proves this point:
The trend only seems to be continuing, so I think it’s time to finally rework the documentation somehow.
private seems counterintuitive to me. San Francisco also has lots of fixed stops for private company shuttles, but these are vehicles that serve the public.
rideshare=* is already used all over the country. rideshare=permit permit=black_car seems to capture the essence of this program.