The Master strip in Ardour is very similar to the other
busses mixer strips.
There are nevertheless a few differences due to the nature of the
Master strip, that is being the last point of treatment before the
output or rendering:
There is no color affected to the master strip
There is exactly one and only one Master Bus Strip for a session, so
it cannot be saved as a template, duplicated or removed in the context
menu, although it can be renamed.
The master strip cannot be hidden or disabled, so there is not
X in the top right, nor an
Active checkbox in the context menu.
It is by definition always solo, so there is no Solo button,
and Iso and Lock are disabled.