In the UI it would be nice to duplicate the selected connection, in the menu "With Selected". 

The copy would be set with the same name plus some suffix (_copy, _1, whatever) and it is useful for when you have a connection with all equal fields except something in a particular one. 
airflow/www/views.py
sqla.func.max(DagRun.start_date).label('start_date'),
        ).group_by(DagRun.dag_id)
        
        query = query.filter(DagRun.dag_id.in_(filter_dag_ids))  
        resp = {
            r.dag_id.replace('.', '__dot__'): {
                'dag_id': r.dag_id,
                'execution_date': r.execution_date.isoformat(),
                'start_date': r.start_date.isoformat(),
            }
            for r in query
        }
        return wwwutils.json_response(resp)
    @expose('/code')
    @auth.has_access(
        [
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG),
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG_CODE),
        ]
    )
    @provide_session
    def code(self, session=None):
        """Dag Code."""
        all_errors = ""
        dag_orm = None
        dag_id = None
        try:
            dag_id = request.args.get('dag_id')
            dag_orm = DagModel.get_dagmodel(dag_id, session=session)
            code = DagCode.get_code_by_fileloc(dag_orm.fileloc)