What is the difference beautifulsoup and bs4

When I go to the beautifulsoup 4.0 documentation, the first page has this information:

(The BeautifulSoup package is probably not what you want. That’s the previous major release, Beautiful Soup 3. Lots of software uses BS3, so it’s still available, but if you’re writing new code you should install beautifulsoup4.)

For those, like me, reading this years later, please note. The above is referring to installing with a system package manager, like apt-get, from which you can install python-bs4 or python3-bs4.

If installing with pip, use pip install beautifulsoup4, currently at V4.7.1.

Since March 2016 there is bs4 package on PyPI The description is

This is a dummy package managed by the developer of Beautiful Soup to prevent name squatting. The official name of PyPI’s Beautiful Soup Python package is beautifulsoup4. This package ensures that if you type pip install bs4 by mistake you will end up with Beautiful Soup.