There are a few things new in 3.9 that need to be documented / have the documentation updated:

* The previous Open Terminal/Open Tab menu items have been unified into a new Open Terminal item (in File menu, and also present now in the appmenu), which opens a new tab or window depending on a new pref "Open new terminals in: [     ]" with "Tab" and "Window" as items in the combo.
  - The old Ctrl-Shift-N / T key shortcuts continue to open a new window/tab regardless of that setting.
  - Clicking the menu item while holding Control inverts the setting, so that if the setting is "Tab" then it opens a window, and v.v.

* There's a new "Use _dark theme variant" pref that makes the terminal use the dark theme variant which some users prefer.

* The "Input method" submenu in the context menu has been removed, since this has also been done in gtk+ for GtkEntry and GtkTextView.

* The appmenu now has a "Quit" item which closes the current window.

* The profile ID is now only shown in the profile preferences dialogue, but not anymore in the profile list in the preferences dialogue.