I have been reading through the documentation of the testing framework (https://devdocs.magento.com/guides/v2.2/mtf/mtf_introduction.html et. al.), which is written in a way that assumes the reader already has used and knows all about selenium. As I do not have any experience with it, some things are not clear to me. First, where is selenium installed? It appears to be on the server. But the server has no browser or graphical interface in its shell. So where do the tests run? On a client with a browser? Or is there something to install on the server to simulate a browser?