The APIs call will result in changes in that view. The coordinator runs every minute by default and applies the current retention rules for each datasource, instructing the historicals to load or unload segments. Some coordinator level dynamic configs also control aspects of how this operates and are documented here.

So in coordinator config, we can set how it should operate as for frequency and so on for retention policies we have set?

We do not want to set the retention rules for each data sources manually in UI but rather create a Python file which makes API requests to set those retention for each data sources and run the Python file via Jenkins pipeline. Do you think does this make sense? It is just because we want to have 1 common source where we can just change retention policies in case we need to change in the future. And an Airflow DAG runs periodically to apply the kill tasks. Are these common ways to achieve in our use cases?

Also, you don't need "manually" trigger kill tasks. This can also be configured to just run periodically within Druid, the basic coordinator config parameters that control this are:

druid.coordinator.kill.on = true #turn on periodic kill tasks
druid.coordinator.kill.period    # how often to run kill tasks defaults to P1D

You can definitely use the Retention Rules API to set the rules from Python. I don't think this is common since retention rules are rarely changed but the APIs are there to be used so, if that works for you, I don't see any reason not to do it that way.