Plain and simple, this adds a new keybinding and menu entry (under the View menu) which allows you to quickly toggle all panes, toolbars and menus.
This will be built-in to Komodo 9.2 by default.
Note when using on Komodo 9.1 that due to a bug in that version the toggle menu entry may not show up in the "unified menu" (burger menu).
To build the Focus Mode addon please refer to the documentation on building an extension:
Note that this addon needs to be built using the --unjarred flag, ie.
koext build --unjarred