{
    "placements":  {
                       "widget-overflow-fixed-list":  [

                                                      ],
                       "nav-bar":  [
                                       "back-button",
                                       "forward-button",
                                       "stop-reload-button",
                                       "home-button",
                                       "customizableui-special-spring1",
                                       "urlbar-container",
                                       "customizableui-special-spring2",
                                       "downloads-button",
                                       "library-button",
                                       "sidebar-button",
                                       "fxa-toolbar-menu-button"
                                   ],
                       "toolbar-menubar":  [
                                               "menubar-items"
                                           ],
                       "TabsToolbar":  [
                                           "tabbrowser-tabs",
                                           "new-tab-button",
                                           "alltabs-button"
                                       ],
                       "PersonalToolbar":  [
                                               "personal-bookmarks"
                                           ]
                   },
    "seen":  [
                 "developer-button"
             ],
    "dirtyAreaCache":  [
                           "nav-bar"
                       ],
    "currentVersion":  16,
    "newElementCount":  2
}