This means the file is compressed. You will need a tool like WinRAR or 7-Zip to extract the actual game data.
Once extracted, this is the "ticket" and "content" package that your console or emulator (like Yuzu or Ryujinx) recognizes as the game. Step 1: Extracting the Data NINJALA-NSP.rar
How to Manage and Install Ninjala via NSP: A Guide to Offline Access This means the file is compressed