What is the default store ID for the admin panel?

In Adobe Commerce, the store ID 0 is specifically reserved for the admin panel scope. This is also referred to as the "global" or "default config" scope. It represents the highest level in the configuration hierarchy, where settings are defined system-wide. These global settings can then be inherited or overridden at more specific levels, such as the website, store group, or store view. The admin panel operates under this ID 0 to manage these foundational configurations.

B. 1: This is the default ID assigned to the first customer-facing store view (e.g., "Default Store View") created during the initial Adobe Commerce installation, not the admin panel.
C. -1: This value is not a standard identifier for any scope within the Adobe Commerce architecture. It is not used to represent the admin panel or any other store entity.

1. Adobe Commerce Developer Documentation, Configuration paths and values: "The admin or global scope is identified by ID 0. The default scope in the coreconfigdata table also refers to the admin or global scope." (Adobe, Configuration paths and values, Configuration section).

2. Adobe Commerce Developer Documentation, Scopes: "The broadest scope is global. This is referred to as the Default Config in the Admin... Any settings that you make at this level will be inherited by every website, store, and store view in your Commerce installation." (Adobe, Scopes, Architecture section).

3. Adobe Commerce Core Code: The core application constant that defines this value can be found in the framework. The class \Magento\Store\Model\Store defines a public constant DEFAULTSTOREID = 0, which is used throughout the application to reference the admin/default scope. (This is an architectural principle reflected in the codebase).