The only physical evidence we have they exist are comets that occasionally show up in the inner solar system where we could observe them which have orbits that are not interstellar but would put them as going incredibly far out. From that we can extrapolate that they likely exist around every star but there is no way we could verify that with our current technology since any light reflected off the objects would be far too faint to detect.
It is the first confirmed interstellar comet and so is the first under the interstellar comet classification, Unfortunate that the headline does not contain that detail however.
It can be authenticated as coming from a trusted party but cannot be authenticated against a user password because the system has no way of knowing any secrets provided by the user.
Python 2 ended support on January 1'st however critical bugs reported before then continued to be worked on until this last release. All Python foundation development has now concluded and any further bug fixes will have to either come from the community or another entity.