It seems that all folders except data and updates will be automatically generated by the system. You can delete Cache (Cache, the previous version of cache will get bigger and bigger, mine once reached 7G) and enCN (English pronunciation, I seem to have deleted it, and the system has been generated again, but the new one is much smaller, so be careful not to choose English pronunciation in the game after deletion). In the update, I only have three files: delete.lst, WOW-0-16016-OSX-final.mpq and WOW-0-16309-win-final.mpq.
The interface is a plug-in folder, and the suffix of the interface is an abandoned plug-in folder, which can be deleted if you are not afraid to download it again.
At present, my server comes with plug-ins and some photos, 19.7G!