EDIT: Hi Developer. Please don't take the comment personally. It's just the tool that didn't work for me. But anyway if you missed detailed commenting, I've got you covered with a quick video capture:

https://youtu.be/j4krs6CNzBE

The contrast listing that has this square with a thick dot in it is confusing because it's not really precise as to where that contrast is in the screen. Best that happens is that when I click one, it anchors me to some point of the page that has that contrast, but it's totally up to me to find where exactly that is. In some rare moments I'm able to locate the highlighted item.

Another thing is the eyedropper feature that felt broken. Sometimes it arbitrarely changes to black or doesn't lock the color I've picked.

Why not make it simpler? Like eyedropping any component would automatically recognizes the contrast ratio with the color in its background, if they're both css colors. Look at the amount of unnecessary information there's on the screen when all some want is just pick and check a contrast ratio.

(I forgot to remove the original post, I might have brought my frustration into unpolite and harsh words instead of being constructive from the beginning. Be sure that I and many people appreciate your effort to come up with something that improves accessibility)