@ecadre i saw this somewhere ..
dbus-send --print-reply --dest=org.gnome.SessionManager /org/gnome/SessionManager org.gnome.SessionManager.GetInhibitors
to get a list of Inhibitor####, and then turn those into something meaningful with
dbus-send --print-reply --dest=org.gnome.SessionManager /org/gnome/SessionManager/InhibitorXXX org.gnome.SessionManager.Inhibitor.GetAppId