Byobu terminal window name asterisk Z

Question

In Byobu terminal window name I know that asterisk Z after window name means that window is zoomed to one split.

But what does asterisk M mean?
There seems to be nothing on this in man pages or its website.

I also noticed that one split in M-marked window has different-looking borders than the other splits.

Answer 1

See the tmux manpage:

       Symbol    Meaning
       *         Denotes the current window.
       -         Marks the last window (previously selected).
       #         Window is monitored and activity has been detected.
       !         A bell has occurred in the window.
       ~         The window has been silent for the monitor-silence
                            interval.
       M         The window contains the marked pane.
       Z         The window's active pane is zoomed.

Full disclosure: I'm the author and maintainer of Byobu.