The package can be uploaded to the repository only by the Plesk administrator. It can be done both through the control panel (the package is uploaded to the server through the form for uploading files) and through the command line. In the second case, an installation package can be uploaded to the server by any means. 

If the package is uploaded through the control panel interface, after the package file is uploaded to the server and unpacked, it goes through the verification process: Plesk checks if there is the info.xml  file in the /info subdirectory of the uploaded application directory. If the file is found there, the required information contained in the file is added to the database. If there is no such file, the application installation is backed off (see <Package Format>).  

In case the package is installed in the system in other way (not through the control panel), the application is registered in the database after the REFRESH button is pressed in the administrator control panel at Server->Application Vault. After this button is pressed, Plesk searches through the repository directory for a new application comparing the directory contents with the records in the database. If a new application is found, the control panel enters information from the file into the database. If no such file is found, the found application is ignored.   

If the package was successfully added to the repository, the application appears in the list of applications already stored in the repository and becomes available for further usage.