I don't know what happened to this extension. It used to be so easy and effective to use. After its redesigned, it's incomprehensible—no wonder you need a tutorial (even then, it's nonsensical now).

Edit (in response to developer):
Hello, and thank you for following up. The extension behaves quite differently from a couple of years ago. If I recall, you could hover or click on text and a persistent, midsize popup would appear—staying open and interactive so you could review details or take notes. Now, the popup is tiny and trails the cursor, which makes it harder to use. It also fails to appear outside private windows, likely due to conflicts with other extensions. In short, it feels over-designed—the kind of counterproductive complexity that’s become too common in tech. If you ever reintroduce an option for the earlier persistent-popup style, I think many of us would appreciate it. Thank you for your work and consideration.

Really useful, I use it basically daily.. it does it job very well...

Incroyablement efficace et pratique !

Game changer

Simply the best in this 'category'. Great job you guys!
Keep it up, please : )

In the short time I have been using this extension I have to say it has exceeded my expectations!
Slick UI without clutter and all the information (and more!) I need as part of my web design workflow.