The Master strip in Ardour is very similar to the other busses mixer strips. The list of differences is (from top to bottom):

• There is no color affected to the master strip
• The master strip cannot be hidden, so there is not X in the top right
• It is by definition always solo, so no Solo, Iso or Lock buttons. It is replaced by a button to show the Monitoring section if the session has one
• It cannot belong to a mix group, so the button is removed.

The Master bus strip is always fixed, at the right end of the mixer, regardless of the scrolling position.