Docker persistent data

Where is the docker persistent data stored filesystem level for general add-ons

For example, I have installed:

And I would like to edit the YMYL for such integration
But not sure how I would be able to do so.

EDIT: removed as this is about add-ons which I donot know how they work

There is no configuration in my repository to map config file to docker, from rtsp simple server perspective, config file is empty (defaulting everything) and I am passing environment variables for some config options, that is it.

If you are interested, you (or I) raise a change on this and allow external config file???