This menu opens the shell console of the node right in the same browser instead of a pop-up window. One of the benefits of opening the shell inside the browser is that sometimes a console opened in a pop-up window does not resize well. That makes the console partially visible, which can be a great annoyance at times when trying to manage the node through the CLI. A console opened through this Shell option will always resize to the full view of the console. The following screenshot shows the Shell window of our node pmx-01:

We can still open the console separately in a browser window using the existing Shell button in the upper-right corner of the GUI, as shown in the following screenshot: