[mrec]

That panel is described in some detail here [1], though even after reading it the click behaviour is very unintuitive. It's explicitly an advanced-user thing, though, and only shown if you click "More" on the basic popup.

[1] https://github.com/gorhill/uBlock/wiki/Quick-guide:-popup-us...

[wtallis]

That link doesn't seem to actually describe the advanced mode panel in any detail at all. The link that does is https://github.com/gorhill/uBlock/wiki/Dynamic-filtering:-qu...