I think all here know what is it 
Here are...
Closed source promotion removed by moderator JTH
New: MBox Viewer (Mar 22, 2026), Platform 30.3 (Mar 29, 2026)
1,400+ portable packages, 1.2 billion downloads
Our costs have risen a bunch. Please donate if you can!
As has been discussed before, all of U3's tools including U3 Action and the U3 installer are 100% closed source/proprietary. Any app that includes U3 Action is Freeware (not 100% open source), so it can't be promoted here.
Sometimes, the impossible can become possible, if you're awesome!
Ok... sorry for this