7-Zip Extra (7za.exe) is used only to extract L2Nyra-Client-*.7z during setup.

License: GNU LGPL (7-Zip Extra), https://www.7-zip.org/license.txt
Source: official https://www.7-zip.org/a/7z2301-extra.7z

Players do not install 7-Zip. The helper runs the redistributable 7za.exe from the setup temp folder.
