Listing of Custom Modules & Listing of Records in Custom Modules

Hi All,

I am trying to fetch all existing custom modules and also trying to fetch all records in a custom module.
But in the API docs:

For Custom modules the API is mentioned as: api/settings/module_customizations/[id]
For Records in a custom module the API is mentioned as: api/custom_module/[entity_name]/[id]

In both of these APIs the ID seems to be a mandatory parameter, that makes sense if I want details of a specific custom module or a specific record in a specific custom module.

But I want to list all records, how to achieve this?

In the GUI the ID of specific custom module or a record inside a custom module is not present, how to get/know the id of a specific record?

Kindly help with the same.