in src/main/resources/SLING-INF/libs/sling/resource-editor/static/js/LoginController.js [63:68]
function setLoginTabLabel(authorizedUser){
$('#login_tab').text(authorized ? 'Logout '+authorizedUser : authorizedUser);
if (authorized) {
$('#login .nav-tabs').removeClass('nav-tabs').addClass('logout');
}
}