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
models.TaskInstance.state: new_state,
                models.TaskInstance.start_date: current_time,
            }
            
            if new_state in State.finished:
                ti_prop_update.update(
                    {
                        models.TaskInstance.end_date: current_time,
                        models.TaskInstance.duration: 0,
                    }
                )
            tis_changed = (
                session.query(models.TaskInstance)
                .filter(
                    models.TaskInstance.dag_id == subq.c.dag_id,
                    models.TaskInstance.task_id == subq.c.task_id,
                    models.TaskInstance.execution_date == subq.c.execution_date,
                )
                .update(ti_prop_update, synchronize_session=False)
            )
        if tis_changed > 0:
            session.flush()
            self.log.warning(
                "Set %s task instances to state=%s as their associated DagRun was not in RUNNING state",
                tis_changed,
                new_state,
            )
            Stats.gauge('scheduler.tasks.without_dagrun', tis_changed)
    @provide_session
    def __get_concurrency_maps(