The developer can test the new feature under the integration environment by deactivating one of the active integration environment branches, creating a new active branch from integration and installing the module, and pushing the changes. This is because Enhanced Integration Environments have a limit of four active branches at a time, and each branch has its own dedicated database and services. The developer can use the Cloud CLI for Commerce tool to manage the branches and deploy the code changes. Verified Reference: [Magento 2.4 DevDocs] 1

The variable env: composer_auth is located in the Project variables section in the Project Web Interface. This variable is used to store the authentication credentials for Composer repositories that require access keys or tokens. The developer can set this variable at the project level to apply it to all environments, or override it at the environment level if needed. Verified Reference: [Magento 2.4 DevDocs] 2

The developer can create a snapshot before deploying a critical feature to their Adobe Commerce Cloud (Pro Plan) production by using the dedicated button on Project Web Interface. A snapshot is a backup of an entire environment, including code, data, media files, and configuration settings. A snapshot can be used to restore an environment to a previous state in case of any issues or errors during deployment or testing. The developer can create a snapshot by accessing the Project Web Interface, choosing an environment, and clicking Create Snapshot. Verified Reference: [Magento 2.4 DevDocs]

The developer can update the Staging environment with the latest code from Production by logging in to the Project Web Interface, choosing the Staging environment, and clicking Sync. This will synchronize the code, data, and media files from Production to Staging, creating an exact copy of Production on Staging. The developer can then deploy the new release to Staging and test it before pushing it to Production. Verified Reference: [Magento 2.4 DevDocs]

According to the Plugins (Interceptors) guide for Magento 2 developers, plugins are class methods that modify the behavior of public class methods by intercepting them and running code before, after, or around them. However, some classes in Magento 2 implement the NoninterceptableInterface interface, which prevents plugins from being generated for them. The Magento\Framework\App\cache\Proxy class is one of them, as it extends from Magento\Framework\ObjectManager\NoninterceptableInterface. Therefore, the plugin is not executing as expected because the target class implements NoninterceptableInterface. Verified Reference: https://devdocs.magento.com/guides/v2.3/extension-dev-guide/plugins.html