Module development and code questions

I'm developing a CMS using the Drupal 9 framework and it only comes with custom entities - hence the Node module is not enabled and will never be. Still, the Claro administrative theme displays the Content tab, and consider it as the default tab when the Content section is displayed.

Of course, the Node module being disabled, there can't be any administrative item to display here.

I assume this tab is hard-coded instead of the tabs list being dynamically constructed based on the registered entities.

Following practices for uploading files that are part of POST  binary files associate with a node in this post, I can see it successfully created by visiting mysite.org/jsonapi/file/file/ 

Hey community,

I'm developing a Drupal module that adds custom entities. These entities - obviously - come with field that are defined in the code by field definitions - instance of Drupal\Core\Field\BaseFieldDefinition.

The problem that I'm facing is that I don't know where the API documentation of the core field definitions is. Typically, I have no idea how to setup a "file" field because I can't find the documentation for the settings that this field definition accept:

In Drupal we can easily manage what fields of a node type are displayed or hidden and in what format (e.g. a text can be plain or html formatted, an image can be original or scaled) within the "manage display" tab.

Now with a headless website when I want to get all nodes of a specific content type, e.g. "GET jsonapi/node/cat" Drupal will return ALL fields with missing formating. But how can I request one of the many view modes that I have defined?

At the moment I am entering information twice once in content type A and again in content Type B.

The fields are the same as I reused them, but are there any clone modules out there that will work with Drupal 10.1.4?

I have searched and none seem to be available for Drupal 10.

The cloned content would be text fields and date content.

Cheers

I have created a content type name "Customer Distribution" to take the population of male and female from different locations.
The fields in this page are:
location
male population
female population
remarks