It could simply be a manual backup created by another user who named it "blu" for personal organization. How to Open blu.7z

Have you stumbled across a file named on your hard drive or in a download folder? Unlike standard .zip files, seeing a .7z extension can be a bit confusing if you don't have the right tools. Here is a quick guide on what this file likely is and how you can peek inside. What is a .7z File?

Choose "7-Zip" > "Extract Here" or "Extract to 'blu'" to see what’s inside. ⚠️ A Note on Safety

Visit the official 7-Zip website and download the version for your OS.