A number of system directories are for security purposes and by default are not displayed in the directory list when connected via FTP... Examples of such directories:
To access the contents of such directories by FTP, you need to connect using any FTP-client and explicitly indicate this in the address bar FTP-client path to the desired directory.
IN FileZilla after connecting, you need to manually register the path to the directory in the field "Remote site»:
IN Total Commander after connecting, you need to enter the command
cd and the path to the directory in the built-in command line:
To clear the directory
.system/tmp from the control panel, use the clear button in detailed information about disk space.