Manual:ImportDump.php

Details
importDump.php file is a maint-scripts>Special:MyLanguage/Manual:Maintenance scripts|maintenance script to import XML dump files into the current wiki. It reads pages from an XML file as produced from Special:Export or , and saves them into the current wiki.

In case you get an error "failed to open stream: No such file or directory", make sure that the specified file does exist and that PHP has access to it.

Examples
or

Troubleshooting
If errors occur when importing files, it may be necessary to use the  option.