
It often refers to Japanese adult video (JAV) series or specialized media collections where codes like "GIA" followed by numbers are standard identifiers.
Use tools like WinRAR or the open-source 7-Zip . For macOS: Use The Unarchiver or Keka .
Since a .rar file is a compressed format, you will need a utility to "extract" or "unrar" it to see what’s inside: