Mods had a "settings" button in the main menu in a previous build. Updated to CS-447596 and that option disappeared.
Specifically, for the Claustrophobia mod, there were options for how long a Dupe had to be "Confined" before triggering the alarm, etc.
I don't think this is a mod issue, because there were multiple mods with "settings" buttons that all disappeared.
Update to CS-447596? Not sure.