<PackageReference Include="Microsoft.Identity.Client" Version="4.84.2-preview" />

Microsoft.Identity.Client.IAccount

public interface IAccount
The IAccount interface represents information about a single account. The same user can be present in different tenants, that is, a user can have multiple accounts. An IAccount is returned in the AuthenticationResult. Account property, and can be used as parameters of PublicClientApplication and ConfidentialClientApplication methods acquiring tokens such as AcquireTokenSilent
string Environment { get; }

Gets a string containing the identity provider for this account, e.g. login.microsoftonline.com.

AccountId of the home account for the user. This uniquely identifies the user across AAD tenants.

string Username { get; }

Gets a string containing the displayable value in UserPrincipalName (UPN) format, e.g. john.doe@contoso.com. This can be null.