You click see the (?) icon to see the summary of the algorithm.
The tool generates unique, meaningful names for any RGB color using a combination of color properties. Every name is unique and reversible - you can convert any name back to its exact RGB color!
Yes, it was obvious that the icons are clickable, and I did see the color picker - but it was a very simple color picker, just a grid of color tiles. Now that you mention it, I realize that there is a second, more advanced color picker, available behind the "+" button in the first picker, and there I can type in hex. I am guessing that the features of the color picker are determined by the browser, and not by your site?