It looks like you’ve come across a file related to Nintendo Switch emulation or homebrew, likely a base game file in .nsp format hosted by Ziperto.

: If the .rar file is only a few megabytes but the game is supposed to be several gigabytes, it might be a fake file or a virus.

The .rar extension means the file is compressed. You'll need a tool like 7-Zip or WinRAR to extract the actual .nsp file inside. 2. Required Keys

Since you're looking for a "good blog post" style explanation of what to do with this, 📂 Understanding the File