lib/Ext/core/class/Loader.js
function() {
            var syncModeEnabled = this.syncModeEnabled;

            if (!syncModeEnabled) {
                this.syncModeEnabled = true;
            }

            this.require.apply(this, arguments);

            if (!syncModeEnabled) {
                this.syncModeEnabled = false;
            }

            this.refreshQueue();
        }
function() {
            var syncModeEnabled = this.syncModeEnabled;

            if (!syncModeEnabled) {
                this.syncModeEnabled = true;
            }

            this.require.apply(this, arguments);

            if (!syncModeEnabled) {
                this.syncModeEnabled = false;
            }

            this.refreshQueue();
        }
documented above