This folder contains the info.xml file that describes the properties of an application, its system requirements, and its configuration parameters. This files serves as a beacon for Plesk Control Panel, informing it about a separate application stored in AV Repository. In other words, if either the info.xml file or the /info folder is missing in the application package, the application package will not be visible to Plesk.
The detailed description of the structure of info.xml is given in the Info.xml File topic of the Reference section.