The name is somewhat ambiguous.
Does it mean to ask the user to "confirmCloseAllTabs"? Or does it mean the act of the user setting the value of this setting to true means to "confirmCloseAllTabs"?
I find your interpretation slightly preferable over what was actually implemented in this case.
"When set to true closing a window with multiple tabs open WILL require confirmation. When set to false closing a window with multiple tabs open WILL NOT require confirmation."
I just checked it and indeed setting it to "false" turns off confirmation.
I find your interpretation slightly preferable over what was actually implemented in this case.