What does pip install ".[full]" do?
Solution 1:
From your current folder ., there is probably a file setup.py. In this file you have some extra options. One of them is full that probably contains the full dependencies for the current package.
So the command, try to install the package in the current folder and all its dependencies. full is just a convenient name, it doesn't mean nothing special for pip (or setup.py)
A better explanation is given here