Just press the flag and it will tell you if you are using it. What is phosphorus? Yes It is an element, but it is also a scratch project to JavaScript converter, it runs your projects faster, but some things don't work so this is use full to use in your projects. How does it work? Method 1 works by moving to a position that would normally be off the screen, and checks to see if it has moved back. Method 2 works by resizing itself to something scratch wouldn't allow but phosphorus allows it, and it checks to see if it has changed it's size back to 100%.
Credit to Hedgehog125_test for the original.