This step is important. It consists in adding a specially created info.xml file to the /info folder of the installation package. This file describes the properties of a web application, its system requirements, and its configuration parameters. It serves as a beacon signaling to Plesk Control Panel about a separate application available in AV Repository. If the info.xml file is missing in the /info folder, the application package will not be visible to Plesk. The detailed description of the structure of the info.xml file can be found in the Reference section of Application Vault SDK documentation. Its Info.xml File subsection can serve as a guide to creating a valid info.xml file.
Thus, this step should result in the info.xml file structured properly and added to the /info folder of the installation package.