File manager

Are already available from sites like portablefreeware.com. They may not be open source, however. I am partial to one named xplorer2 lite. Check out what works for you.

There are many references to this throughout the forums. Please search next time.

I use (an expired version of) XYplorer. It still works after expiration, but you'll always have that startup screen unless you register.

There's no reason to make a comment for something so trivial.

Total Commander is portable out of the box.