I want change the order of items in the toolbar. Where can I do this?
Actions are ordered from the plone state adapter, so the order on the portal_actions tool ( actions.xml file on the profile ) and the order of the big blocks depends on the plone.toolbar viewlet manager (by default there is only the contentviews as I remember).
There is an exception ['folderContents', 'edit', 'view'] , this are forced on plone.app.layout.viewlets.common.py:281 to be contentviews before the contentmenu options and then the other contentviews.
If you want to break this rules you will need to overwrite the viewlet. @vangheem can bring some more light to it !