https://github.com/apache/airflow/pull/12139 added some new params to the scheduler -- we have "cursory" docs for them in the comments in the config file, but we should have a more details docs in the scheduler.rst page.
airflow/jobs/scheduler_job.py
)
        for task_instance in tis_to_set_to_scheduled:
            self.executor.queued_tasks.pop(task_instance.key)
        task_instance_str = "\n\t".join(repr(x) for x in tis_to_set_to_scheduled)
        self.log.info("Set the following tasks to scheduled state:\n\t%s", task_instance_str)
    @provide_session
    def _process_executor_events(self, session: Session = None) -> int:
        """Respond to executor events."""
        if not self.processor_agent:
            raise ValueError("Processor agent is not started.")
        ti_primary_key_to_try_number_map: Dict[Tuple[str, str, datetime.datetime], int] = {}
        event_buffer = self.executor.get_event_buffer()
        tis_with_right_state: List[TaskInstanceKey] = []
        
        for ti_key, value in event_buffer.items():
            state: str
            state, _ = value
            
            ti_primary_key_to_try_number_map[ti_key.primary] = ti_key.try_number
            self.log.info(
                "Executor reports execution of %s.%s execution_date=%s "
                "exited with status %s for try_number %s",
                ti_key.dag_id,
                ti_key.task_id,
                ti_key.execution_date,
                state,
                ti_key.try_number,
            )
            if state in (State.FAILED, State.SUCCESS, State.QUEUED):
                tis_with_right_state.append(ti_key)