You got a notification about error that occurred on a production environment. The merchant gave you the error
identifier.
How do you find the error message based on the identifier?

You have created a new section in system configuration under the Catalog tab:

How do you restrict an access to the section using Magento ACL?

You are writing a customization for the customer module. You need to make sure the configuration files from your module are loaded after the customer module's configuration.
Where should the dependency be declared?

You are working on a Magento store which will be selling in two countries. Each country has its own set of
payment methods.
How do you organize the project to support this requirement?

\Magento\Sales\Model\Api\OrderRepositoryInterface::getList accepts a SearchCriteriaInterface to filter and sort information.
What class assists in creating an instance for SearchCriteriaInterface?